Molbank 2008, M576

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Short Note

3-Dimethylaminomethylene-4-phenyl-1,3-dihydro-2H-1,5-benzodiazepin-2-one

Abdelouahhab El Rhazi, Abdesselam Baouid,* Said Elhazazi, Aicha Boudina and
Mohamed Essaber

Laboratoire de Chimie Moléculaire, Equipe de Chimie des Hétérocycles et Valorisation des Extraits des Plantes, Département de Chimie, Faculté des Sciences-Semlalia, Université Cadi Ayyad, B.P 2390, 40001 Marrakech, Maroc. E-mail: [email protected], [email protected], [email protected], [email protected], [email protected]

* Author to whom correspondence should be addressed.

Received: 23 July 2008 / Accepted: 27 August 2008 / Published: 4 September 2008

 

Keywords: 1,5-Benzodiazepin-2-one, dimethylformamide-dimethylacetal.

 

 

In this paper, we describe a facile and efficient method to prepare compound 2, which had been previously obtained by a Vilsmeier reaction using DMF/POCl3 [1]. We found that employment of dimethylformamide-dimethylacetal (DMF-DMA) affords the title compound in better purity and higher yield.

 

 

A mixture of 0.47 g (1.98 mmol) of 4-phenyl-1,3-dihydro-2H-1,5-benzodiazepin-2-one 1 [2,3] in 4.5 ml of dimethylformamide-dimethylacetal (DMF-DMA) was stirred at 100 °C for 4 hours and then cooled to room temperature. Filtration and washing with a little cold diethyl ether gave 0.46 g (75%) of 3-dimethylaminomethylene-4-phenyl-1,3-dihydro-2H-1,5-benzodiazepin-2-one 2. The product obtained was recrystallized from diethyl ether.

 

Melting point: 224-225 °C (Diethyl ether).

 

MS (m/z, %): 292 ([M+H]+, 100%).

 

1H NMR (CDCl3, 400 MHz), d(ppm): 2.55 (s, 6H, (CH3)2N), 2.80 (s, 1H, NH), 7.40 (s, 1H, C=CH-N(CH3)2), 6.80-7.90 (m, 9H, H-Ar).

 

13C NMR (CDCl3, 100 MHz), d(ppm): 43.50 (N(CH3)2), 98.02 (C-3), 121.47, 124.59, 127.34, 128.13, 128.67, 128.89, 130.65, 131.78, 141.86 (C-Ar), 151.18 (C=CH-N(CH3)2), 167.40 (C-4), 178.57 (C=O).

 

References:

1.      Solomko, Z.F.; Proshkina, V.N.; Bozhanova, N.Ya.; Loban, S.V.; Babichenko, L.N. Vilsmeier reaction with 4-phenyl-2,3-dihydro-1H-1,5-benzodiazepin-2-one. Khim. Geterosikl. Soedin. 1984, 223.

2.      Ried, W.; Stahlhofen, P. Über heterocyclische siebenringsysteme, vii der reaktionsverlauf zwischen o-phenylendiamin und alkyliden-brenztraubensäuren. Chem. Ber. 1957, 90, 828.

3.      Nardi, D.; Tajana, A.; Rossi, S. J. Heterocyclic compounds from 3,3-dimercapto-1-aryl-2-propen-1-ones. Note 1. 4-aryl-1,3-dihydro-2H-1,5-benzodiazepine-2-thiones. Heterocyc. Chem. 1973, 10, 815.

 

© 2008 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).