128589-58-2Relevant articles and documents
Heterocyclic systems containing bridgehead nitrogen atom: Part LXX - Reaction of 3,4-dihydroquinazoline-2-thione with α-halogenoketones
Dahiya,Kumar,Pujari
, p. 443 - 446 (2007/10/02)
3,4-Dihydroquinazoline-2-thione (I), obtained from the reaction of 2-aminobenzylamine with carbon disulphide, on condensation with chloroacetone yields 5H-3-methylthiazolo[2,3-b]quinazoline hydrochloride (II) which on basification gave a product (m.p. 174°) for which structure III was assigned [Sykes P, J chem Soc, 2390 (1955)]. In the present study the structure of this product has been modified to IV on the basis of IR, 1H NMR and mass spectral data. II on basification actually gives the free base III (m.p. 115°) the aerial oxidation of which or keeping it at 80° for 72 hr furnishes IV. The reaction of thione I with p-methoxyphenacyl bromide affords 5H-3-(p-anisyl)thiazolo[2,3-b]quinazoline (V) while with p-nitrophenacyl bromide and p-bromophenacyl bromide it gives carbinol-amine compounds (VIa,b) which on heating furnishes the dehydrated cyclized compounds (VIIa,b). The structural assignment for the oxidation product as IV rather than IX, settles the structural ambiguity of the cyclized products obtained from the reaction of I with α-halogenoketones as III, V and VI.
