M. Giasuddin Ahmed

Synthesis of Substituted Tetrahydrochromenes by the Reactions of α,β-Unsaturated Cyanoesters with Dimedone/1,3-Cyclohexanedione

Abstract Ethyl esters of 2-cyano-3-arylacrylic acid 1a–d (a = 4-CH3-C6H4-, b = 4-N(CH3)2-C6H4-, c = 2-CH3O-C6H4-, d = 2-Cl-C6H4-) reacted with 5,5-dimethyl-1,3-cyclohexanedione (2p, Y=CH3), and 1e–g (e = 4-CH3-C6H4-, f = 2-CH3O-C6H4-, g = 2-Cl-C6H4-) reacted with 1,3-cyclohexanedione (2q, Y=H) in the presence of alcoholic sodium ethoxide to give the corresponding ethyl esters of 2-amino-7,7-dimethyl-5-oxo-4-aryl-5,6,7,8-tetrahydro-4H-chromene-3-carboxylic acid 4a–d and 2-amino-5-oxo-4-aryl-5,6,7,8-tetrahydro-4H-chromene-3-carboxylic acid 4e–g. The structures of the compounds 4a–g were confirmed by their ultraviolet, infrared, 1H NMR, 13C NMR, and mass spectral data and elemental analyses.

Synthesis of some substituted adamantane-2,4-diones from 4, 4-disubstituted cyclohexanone enamines and methacryloyl chloride

The reaction of methacryloyl chloride with the morpholine enamine 4a derived from 4-acetyl-4-isopropenylcyclo-hexanone 3a gave 4,6-anti-6-hydroxy-5,6-dimethyl-7-isopropenyladamantane-2,4-dione 6a and 4,6-syn-6-hydroxy-5,6-dimethyl-7-isopropenyladamantane-2, 4-dione 7a as racemates epimeric at 6-C. Comparable results were found for the corresponding phenyl and benzyl substituted cyclohexanones 3b and 3c. In the case of the methyl-substituted cyclohexanone 3d 4,6- anti-alcohol 7d was isolated in pure form.

Synthesis of 7,11-diaryl-3-oxo (or thioxo)-2,4-diazaspiro[5.5]undecane-1,5,9-triones, Part I

Spiro compounds 7,11-diaryl-2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraones 3a–e and 7,11-diaryl-3-thioxo-2,4-diazaspiro[5.5]undecane-1,5,9-triones 3f–j were prepared from the reaction of 1,5-diaryl-1,4-pentadien-3-ones 2a–f with barbituric acid (1a) and 2-thiobarbituric acid (1b). The structures of the products were confirmed by UV, IR, 1H and 13C NMR, MS and elemental analysis.

Synthesis of substituted tricyclo[5.3.1.04,9]undecan-2,6-diones

Abstract The morpholine enamines of 4-acetyl-4-phenylcyclohexanone 3a , 4-acetyl-4-isopropenylcyclohexanone 3b , 4-acetyl-4-methylcyclohexanone 3c react with acryloyl chloride to give 1-phenyl-4( N -morpholino)tricyclo[5.3.1.0 4,9 ]undecan-2,6-dione 9a , 1-isopropenyl-4( N -morpholino)tricyclo[5.3.1.0 4,9 ]undecan-2,6-dione 9b , and 1-methyl-4( N -morpholino)tricyclo[5.3.1.0 4,9 ]undecan-2,6-dione 9c , respectively, along with the corresponding substituted adamantane-2,4-diones. The morpholine enamine of 4-acetyl-4-benzylcyclohexa-none 3d and pyrrolidine enamine of 4-acetyl-4-phenylcyclohexanone 3a yield the corresponding 1-benzyl-4( N -morpholino)tricyclo[5.3.1.0 4,9 ]undecan-2,6-dione 9d and 8( R )-methyl-1-phenyl-4( N -pyrrolidinyl)tricyclo[5.3.1.0 4,9 ]undecan-2,6-dione 9e . No substituted adamantane-2,4-diones were formed in any of the latter two reactions.

Synthesis of Some Substituted Adamantane-2,4-diones from 4,4-Disubstituted Cyclohexanone Enamines and α,β-Unsaturated Acid Chlorides

Following our previous report7 on the synthesis of adamantane derivatives by condensation of 4,4-disubstituted cyclohexanone enamines with α,β-unsaturated acid chlorides, we now report the synthesis of seven new substituted adamantanediones from the reactions of three cyclohexanone enamines (4, Y=phenyl, isopropenyl, methyl) in which one of the substituents is an acetyl group.

Synthesis of 8-Aroyl-9-hydroxy-7,9,11-triaryl-3-oxo(or thioxo)-2,4-diazaspiro[5.5]undecane-1,5-diones

Abstract A number of 8-aroyl-9-hydroxy-7,9,11-triaryl-3-oxo(or thioxo)-2,4-diazaspiro[5.5]undecane-1,5-diones 3a–g were synthesized from the reaction of 1,3-diaryl-2-propen-1-ones 2a–d with barbituric acid 1a and 2-thiobarbituric acid 1b in 50% aqueous ethanol under refluxing conditions without using any catalyst. The structures of the compounds were confirmed by ultraviolet, infrared, 1H and 13C NMR, mass, and elemental analysis. GRAPHICAL ABSTRACT

Synthesis of substituted tricyclo[5.3.1.04,9]undecan-2,6-dione from 4,4-disubstituted cyclohexanone enamines and methacryloyl chloride

Abstract Morpholine enamines 4‐acetyl‐4‐methyl‐1‐morpholinocyclohexene 4a, 4‐acetyl‐4‐phenyl‐1‐morpholinocyclohexene 4b, and 4‐acetyl‐4‐isopropenyl‐1‐morpholinocyclohexene 4c react with methacryloyl chloride to give 1,7‐dimethyl‐4(N‐morpholino) tricyclo[5.3.1.04,9]undecan‐2,6‐dione 9a , 1‐phenyl‐7‐methyl‐4(N‐morpholino) tricyclo[5.3.1.04,9]undecan‐2,6‐dione 9b , and 1‐ispropenyl‐7‐methyl‐4(N‐morpholino) tricyclo[5.3.1.04,9]undecan‐2,6‐dione 9c respectively, along with the corresponding substituted adamandane‐2,4‐diones.