No abstract

The reaction of α‐cyanothioacetamide (1) or its methylthio derivative (2) with anthranilic acid led to the formation of 3,4‐dihydro‐4‐oxoquinazolin‐2‐yl acetonitrile (3). 3 condensed with aromatic aldehydes to give arylidene derivatives (4a‐d) which could be prepared also via the reaction of 2‐thiocarbamoylcinnamonitriles (5a‐d) or their methylthio derivatives (6a‐d) with anthranilic acid. 3 reacted with cinnamonitrile derivatives (7a‐h) and (12a‐d) to yield pyrido‐[1,2‐a]‐quinazoline derivatives (10a‐h) and (15a‐d) which could also be prepared by the reaction of (4a‐d) with malononitrile (11a), benzoyl acetonitrile (11b) and ethylcyanoacetate (16), respectively.

The action of hydrazine hydrate on 5‐arylidene‐3‐aryl‐2‐methylmercaptohydantoins led to ring opening and rearrangement into 5‐arylidene‐3‐amino‐N2‐aryl‐glycocyamidines (9a‐f). The structure of the products 9a‐f was established and the mechanism of their formation was discussed.

2-Mercapto-4-amino-5-cyano-6-arylpyrimidines (1a, b), 2-hydroxy derivatives 1c, d and 2-methylmercapto derivatives 4 a, b were synthesised via the reaction of either a mixture of malononitrile and aromatic aldehyde or arylidene malononitrile with thiourea, urea and S-methylisothiourea, respectively. 1c, d could also be obtained by the action of hydrogen peroxide on 1a, b or by the action of hydrochloric acid on 4a, b. Compounds 4a, b could also be prepared by the action of methyl iodide on 1a, b. 4a reacted with hydrazine hydrate to give the 2-hydrazino derivative 5 which condensed easily with aromatic aldehydes to give the Schiff’s bases 6 a, b. Compound 5 could be converted into the tetrazolo-and s-triazolopyrimidines 7 and 9 by the action of nitrous acid and carbon disulphide respectively. Structures of the newly synthesised compounds were established by chemical routes and spectral studies

4-Thiohydantoin and 1-phenyl-4-thiohydantoin reacted with aromatic aldehydes to give the corresponding 5-arylidene-4-thiohydantoin (1 a-h). la was obtained also from 5-benzylidene hydantoin and phosphorous pentasulphide. Grignard reagents added to the lateral double bond of (1 a-c) to give after hydrolysis the colorless products 3. Treatment of (1a, b) with alkylating agents gave the corresponding alkylmercapto derivatives (4 a-h). Also (4a, e) were obtained by the action of ethereal diazomethane on (1a, b). By further methylation of (4 e) with diazomethane, a cyclopropane derivative could be isolated.