Efficient Room‐Temperature One‐Pot Synthesis of 2‐Amino‐3‐alkyl(3‐aryl)quinazolin‐4(3H)‐ones

Abstract

Starting from anthranilates, the one‐pot successive addition of ethoxycarbonylisothiocyanate, alkyl‐ or arylamines, and the coupling reagent EDCI led to the clean, room‐temperature formation of carbamate‐protected 2‐amino‐3‐alkyl(3‐aryl)quinazolin‐4(3H)‐ones in up to 93 % yield. This method provides a practical alternative to previously reported procedures for the synthesis of 2‐amino‐3‐substituted quinazolin‐4(3H)‐ones.

Expanding a fluorescent RNA alphabet: synthesis, photophysics and utility of isothiazole-derived purine nucleoside surrogates

“…Employing ethoxycarbonyl isothiocyanate and EDC in a mild 1-pot, 2 step synthesis, as reported by Fabis et al , gave the desired product, starting from the ester-substituted substrate 18a (Scheme 5). 31 The same method, used with the amide 18b , yielded the isoguanosine analogue 26 . The diamino purine analogue ( 23 ) was also found to be formed in low (<5%) yield but could not be cleanly isolated.…”

Aminopyrazine Pathway to the Moco Metabolite Dephospho Form A

“…[20] We turned to the condensation of ethoxycarbonylisothiocyanate (SCNCO 2 Et) with amino-substituted heterocycles, since Stanovnik et al had reactedb enzyl 3-aminopyrazine-2-carboxylate with SCNCO 2 Et in boilingc hloroform and obtained the corresponding3 -thioureidopyrazine-2-carboxylate, which was cyclized further to 2-thioxo-2,3-dihydropteridin-4(1H)-one. [23] Ther eaction is assumed to start with the conversion of the thiourea moiety to a carbodiimide by treatment with EDCI. [22] Fabis et al had accessed N-3 unsubstituted quinazolones from anthranilic acid esters and SCNCO 2 Et, followed by activation of the thiourea with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) and reactionw ith hexamethyldisilazane.…”

Fragment Discovery for the Design of Nitrogen Heterocycles as Mycobacterium tuberculosis Dihydrofolate Reductase Inhibitors

“…Mp 260°C ; IR (KBr): v max 3324,2, 3123.2, 3071.4, 1666.2, 1612.2, 510.2 cm −1 ; 1 H NMR (300 MHz, CDCl 3 ): δ ppm 7.40–7.73 (m, 4H), 8.23 (s, 2H), 11.93 (s, 1H).…”