US4207228A
Expired / Lapsed
US
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UV-Light-stabilized compositions containing substituted 1,5-diazacycloalkanes, novel compounds and synthesis thereof
Assignee: Goodrich Corp
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Filing: 1977-09-21
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Granted: 1980-06-10
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Expires: 1997-09-21
Abstract
Abstract Novel polysubstituted 1,5-diazacycloalkanes and polysubstituted 2-keto-1,5-diazacycloalkanes are powerful stabilizers for materials subject to ultraviolet (UV) light degradation, particularly for polyolefins. The cyclic compounds of this invention have (a) a fixed three-carbon bridge between the N 1 and N 5 atoms of the diaza ring, the remaining portion of the ring having a variable length bridge of two or more carbon atoms, (b) an N-adjacent carbon atom of the diaza ring is polysubstituted, that is, has two substituents which may be cyclizable. Compositions containing (a) the polysubstituted 1,5-diazacycloalkanes and polysubstituted 2-keto-1,5-diazacycloalkanes of this invention, and (b) prior art polysubstituted 1,5-diazacycloalkanes and polysubstituted 2-keto-1,5-diazacycloalkanes, exhibit excellent stability to UV light. A novel synthesis for preparing polysubstituted 2-keto-1,5-diazacycloalkanes is disclosed.
Inventors
- 👤 John T. Lai
- 👤 Pyong N. Son
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:31
CPC Classifications
C; C07; C07D; C07D243/00; C07D243/06; C07D243/10; C07D243/12; C07D243/08; C08; C08K; C08K5/00; C08K5/16; C08K5/34; C08K5/3442
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
425 words
A class of mono-keto compounds comprising polysubstituted monocyclic 2-keto-1,5-diazacycloalkanes having a fixed three-carbon bridge between the N 1 and N 5 atoms of the diaza ring, and dimers and bis compounds thereof containing plural 1,5-diazacycloalkan-2-one moieties, said mono-keto compounds having a formula selected from ##STR15## wherein, said dimers and bis compounds consist essentially of two said moieties connected through N atoms thereof; R 1 and R 4 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, hydroxyalkyl having from 1 to about 12 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, ether having from 3 to about 18 carbon atoms, hydroxyalkyl ether having from 4 to about 18 carbon atoms, cyanoalkyl ether having from 4 to about 18 carbon atoms, alkenyl having from 7 to about 14 carbon atoms, aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cycloalkyl having from 6 to about 7 carbon atoms; R 4 optionally also represents oxygen; R 2 and R 3 independently represent alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, cycloalkyl having from 5 to about 14 carbon atoms, hydroxycycloalkyl having from 5 to about 14 carbon atoms, aminoalkyl or iminoalkyl having from 2 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cyclizable alkylene together having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms; and, R 5 , R 6 , R 7 , and R 8 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, and cyclizable alkylene, R 5 , R 6 together, or R 7 , R 8 together, having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms.
Claim 2
Dependent Claim
425 words
A class of mono-keto compounds comprising polysubstituted monocyclic 2-keto-1,5-diazacycloalkanes having a fixed three-carbon bridge between the N 1 and N 5 atoms of the diaza ring, and dimers and bis compounds thereof containing plural 1,5-diazacycloalkan-2-one moieties, said mono-keto compounds having a formula selected from ##STR15## wherein, said dimers and bis compounds consist essentially of two said moieties connected through N atoms thereof; R 1 and R 4 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, hydroxyalkyl having from 1 to about 12 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, ether having from 3 to about 18 carbon atoms, hydroxyalkyl ether having from 4 to about 18 carbon atoms, cyanoalkyl ether having from 4 to about 18 carbon atoms, alkenyl having from 7 to about 14 carbon atoms, aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cycloalkyl having from 6 to about 7 carbon atoms; R 4 optionally also represents oxygen; R 2 and R 3 independently represent alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, cycloalkyl having from 5 to about 14 carbon atoms, hydroxycycloalkyl having from 5 to about 14 carbon atoms, aminoalkyl or iminoalkyl having from 2 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cyclizable alkylene together having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms; and, R 5 , R 6 , R 7 , and R 8 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, and cyclizable alkylene, R 5 , R 6 together, or R 7 , R 8 together, having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms.
Claim 3
Dependent Claim
49 words
The 2-keto-1,5-diazacycloalkanes of claim 1 wherein R 1 or R 4 or each is alkyl having from 1 to about 20 carbon atoms, and, R 2 , R 3 , R 7 , and R 8 , are each lower alkyl having from 1 to about 5 carbon atoms.
Claim 4
Dependent Claim
46 words
The 2-keto-1,5-diazacycloalkanes of claim 1 wherein R 1 or R 4 or each is alkyl having from 1 to about 20 carbon atoms, R 2 , R 3 , R 5 and R 6 are each lower alkyl having from 1 to about 5 carbon atoms.
Claim 5
Dependent Claim
29 words
The 2-keto-1,5-diazacycloalkanes of claim 1 selected from the group consisting of cis-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; trans-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; cis-N 1 -methyl-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; cis-N 1 -dodecyl-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; cis-N 1 -benzyl-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; trans-N 1 -dodecyl-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; and, cis-N 5 -(β-hydroxyethyl)-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one.
Claim 6
Dependent Claim
308 words
A composition of matter resistant to degradation by ultraviolet light comprising a compound subject to ultraviolet light degradation having dispersed therein from about 0.01 part to about 5 parts by weight of a polysubstituted monocyclic 2-keto-1,5-diazacycloalkane stabilizer compound, per 100 parts of said compound, said stabilizer compound being represented by a structure selected from the group consisting of ##STR16## wherein, R 1 and R 4 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, hydroxyalkyl having from 1 to about 12 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, ether having from 3 to about 18 carbon atoms, hydroxyalkyl ether having from 4 to about 18 carbon atoms, cyanoalkyl ether having from 4 to about 18 carbon atoms, alkenyl having from 7 to about 14 carbon atoms, aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cycloalkyl having from 6 to about 7 carbon atoms; R 4 optionally also represents oxygen; and, R 2 and R 3 independently represent alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, cycloalkyl having from 5 to about 14 carbon atoms, hydroxycycloalkyl having from 5 to about 14 carbon atoms, aminoalkyl or iminoalkyl having from 2 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cyclizable alkylene together having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms.
Claim 7
Dependent Claim
308 words
A composition of matter resistant to degradation by ultraviolet light comprising a compound subject to ultraviolet light degradation having dispersed therein from about 0.01 part to about 5 parts by weight of a polysubstituted monocyclic 2-keto-1,5-diazacycloalkane stabilizer compound, per 100 parts of said compound, said stabilizer compound being represented by a structure selected from the group consisting of ##STR16## wherein, R 1 and R 4 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, hydroxyalkyl having from 1 to about 12 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, ether having from 3 to about 18 carbon atoms, hydroxyalkyl ether having from 4 to about 18 carbon atoms, cyanoalkyl ether having from 4 to about 18 carbon atoms, alkenyl having from 7 to about 14 carbon atoms, aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cycloalkyl having from 6 to about 7 carbon atoms; R 4 optionally also represents oxygen; and, R 2 and R 3 independently represent alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, cycloalkyl having from 5 to about 14 carbon atoms, hydroxycycloalkyl having from 5 to about 14 carbon atoms, aminoalkyl or iminoalkyl having from 2 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cyclizable alkylene together having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms.
Claim 8
Dependent Claim
27 words
The composition of claim 5 wherein said compound is selected from the group consisting of polyhydrocarbons, polyesters, polyester resin, polyamides, vinyl polymers, cellulose ether, and cellulose esters.
Claim 9
Dependent Claim
61 words
The composition of claim 6 wherein said compound is a solid and said 2-keto-1,5-diazacycloalkanes have a structure wherein R 1 or R 4 or each is alkyl having from 1 to about 20 carbon atoms, and, R 2 , R 3 , R 7 , and R 8 , are each lower alkyl having from 1 to about 5 carbon atoms.
Claim 10
Dependent Claim
58 words
The composition of claim 6 wherein said compound is a solid and said 2-keto-1,5-diazacycloalkanes have a structure wherein R 1 or R 4 or each is alkyl having from 1 to about 20 carbon atoms, R 2 , R 3 , R 5 and R 6 are each lower alkyl having from 1 to about 5 carbon atoms.
Claim 11
Dependent Claim
39 words
The composition of claim 6 wherein said compound is a solid and said 2-keto-1,5-diazacycloalkanes are selected from the group consisting of cis-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; trans-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; cis-N 1 -methyl-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; cis-N 1 -dodecyl-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; cis-N 1 -benzyl-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; trans-N 1 -dodecyl-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one; and, cis-N 5 -(β-hydroxyethyl)-4,4-dimethyl-decahydro-1,5-benzodiazepin-2-one.
Claim 12
Dependent Claim
425 words
A class of mono-keto compounds comprising polysubstituted bicyclic 2-keto-1,5-diazacycloalkanes having a fixed three-carbon bridge between the N 1 and N 5 atoms of the diaza ring, and dimers and bis compounds thereof containing plural 1,5-diazacycloalkan-2-one moieties, said mono-keto compounds having a formula selected from ##STR17## wherein, said dimers and bis compounds consist essentially of two said moieties connected through N atoms thereof; R 1 and R 4 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, hydroxyalkyl having from 1 to about 12 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, ether having from 3 to about 18 carbon atoms, hydroxyalkyl ether having from 4 to about 18 carbon atoms, cyanoalkyl ether having from 4 to about 18 carbon atoms, alkenyl having from 7 to about 14 carbon atoms, aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cycloalkyl having from 6 to about 7 carbon atoms; R 4 optionally also represents oxygen; R 2 and R 3 independently represent alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, cycloalkyl having from 5 to about 14 carbon atoms, hydroxycycloalkyl having from 5 to about 14 carbon atoms, aminoalkyl or iminoalkyl having from 2 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cyclizable alkylene together having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms; and, R 5 , R 6 , R 7 , and R 8 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, and cyclizable alkylene, R 5 , R 6 together, or R 7 , R 8 together, having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms.
Claim 13
Dependent Claim
425 words
A class of mono-keto compounds comprising polysubstituted bicyclic 2-keto-1,5-diazacycloalkanes having a fixed three-carbon bridge between the N 1 and N 5 atoms of the diaza ring, and dimers and bis compounds thereof containing plural 1,5-diazacycloalkan-2-one moieties, said mono-keto compounds having a formula selected from ##STR17## wherein, said dimers and bis compounds consist essentially of two said moieties connected through N atoms thereof; R 1 and R 4 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, hydroxyalkyl having from 1 to about 12 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, ether having from 3 to about 18 carbon atoms, hydroxyalkyl ether having from 4 to about 18 carbon atoms, cyanoalkyl ether having from 4 to about 18 carbon atoms, alkenyl having from 7 to about 14 carbon atoms, aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cycloalkyl having from 6 to about 7 carbon atoms; R 4 optionally also represents oxygen; R 2 and R 3 independently represent alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, cycloalkyl having from 5 to about 14 carbon atoms, hydroxycycloalkyl having from 5 to about 14 carbon atoms, aminoalkyl or iminoalkyl having from 2 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cyclizable alkylene together having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms; and, R 5 , R 6 , R 7 , and R 8 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, and cyclizable alkylene, R 5 , R 6 together, or R 7 , R 8 together, having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms.
Claim 14
Dependent Claim
49 words
The 2-keto-1,5-diazacycloalkanes of claim 10 wherein R 1 or R 4 or each is alkyl having from 1 to about 20 carbon atoms, and, R 2 , R 3 , R 7 , and R 8 , are each lower alkyl having from 1 to about 5 carbon atoms.
Claim 15
Dependent Claim
46 words
The 2-keto-1,5-diazacycloalkanes of claim 10 wherein R 1 or R 4 or each is alkyl having from 1 to about 20 carbon atoms, R 2 , R 3 , R 5 and R 6 are each lower alkyl having from 1 to about 5 carbon atoms.
Claim 16
Dependent Claim
308 words
A composition of matter resistant to degradation by ultraviolet light comprising a compound subject to ultraviolet light degradation having dispersed therein from about 0.01 part to about 5 parts by weight of a bicyclic polysubstituted 2-keto-1,5-diazacycloalkane stabilizer compound, per 100 parts of said compound, said stabilizer compound being represented by a structure selected from the group consisting of ##STR18## wherein, R 1 and R 4 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, hydroxyalkyl having from 1 to about 12 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, ether having from 3 to about 18 carbon atoms, hydroxyalkyl ether having from 4 to about 18 carbon atoms, cyanoalkyl ether having from 4 to about 18 carbon atoms, alkenyl having from 7 to about 14 carbon atoms, aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cycloalkyl having from 6 to about 7 carbon atoms; R 4 optionally also represents oxygen; and, R 2 and R 3 independently represent alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, cycloalkyl having from 5 to about 14 carbon atoms, hydroxycycloalkyl having from 5 to about 14 carbon atoms, aminoalkyl or iminoalkyl having from 2 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cyclizable alkylene together having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms.
Claim 17
Dependent Claim
308 words
A composition of matter resistant to degradation by ultraviolet light comprising a compound subject to ultraviolet light degradation having dispersed therein from about 0.01 part to about 5 parts by weight of a bicyclic polysubstituted 2-keto-1,5-diazacycloalkane stabilizer compound, per 100 parts of said compound, said stabilizer compound being represented by a structure selected from the group consisting of ##STR18## wherein, R 1 and R 4 independently represent hydrogen, alkyl having from 1 to about 24 carbon atoms, hydroxyalkyl having from 1 to about 12 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, aminoalkyl or iminoalkyl having from 1 to about 12 carbon atoms, ether having from 3 to about 18 carbon atoms, hydroxyalkyl ether having from 4 to about 18 carbon atoms, cyanoalkyl ether having from 4 to about 18 carbon atoms, alkenyl having from 7 to about 14 carbon atoms, aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cycloalkyl having from 6 to about 7 carbon atoms; R 4 optionally also represents oxygen; and, R 2 and R 3 independently represent alkyl having from 1 to about 24 carbon atoms, haloalkyl having from 1 to about 12 carbon atoms, cyanoalkyl having from 2 to about 12 carbon atoms, cycloalkyl having from 5 to about 14 carbon atoms, hydroxycycloalkyl having from 5 to about 14 carbon atoms, aminoalkyl or iminoalkyl having from 2 to about 12 carbon atoms, alkenyl or aralkyl having from 7 to about 14 carbon atoms, carboalkoxy having from 1 to 7 carbon atoms, and cyclizable alkylene together having from 5 to about 6 carbon atoms which alkylene together with the carbon atom of the diaza ring to which said alkylene is bound represents cycloalkyl having from 6 to about 7 carbon atoms.
Claim 18
Dependent Claim
27 words
The composition of claim 13 wherein said compound is selected from the group consisting of polyhydrocarbons, polyesters, polyester resins, polyamides, vinyl polymers, cellulose ether, and cellulose esters.
Claim 19
Dependent Claim
61 words
The composition of claim 14 wherein said compound is a solid and said 2-keto-1,5-diazacycloalkanes have a structure wherein R 1 or R 4 or each is alkyl having from 1 to about 20 carbon atoms, and, R 2 , R 3 , R 7 , and R 8 , are each lower alkyl having from 1 to about 5 carbon atoms.
Claim 20
Dependent Claim
58 words
The composition of claim 14 wherein said compound is a solid and said 2-keto-1,5-diazacycloalkanes have a structure wherein R 1 or R 4 or each is alkyl having from 1 to about 20 carbon atoms, R 2 , R 3 , R 5 and R 6 are each lower alkyl having from 1 to about 5 carbon atoms.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-06-10 | 1983-12-10 | 1984-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-06-10 | 1987-12-10 | 1988-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-06-10 | 1991-12-10 | 1992-06-10 | $7700.00 | Window Closed / Lapsed |