A new synthesis of 4‐cyano‐1,3‐dihydro‐2‐oxo‐2H‐imidazole‐5‐(N¹‐tosy1)carboxamide : reactive precursor for thiopurine analogues

Abstract

N‐[(5‐Cyano‐2‐oxoimidazolidin‐4‐yl)‐iminomethyl]‐p‐toluensulfonamide 3 was prepared in fairly good yield by the base catalyzed cyclisation of N‐[(Z)‐2‐amino‐1,2‐dicycanovinylcarbamoyl]‐p‐toluenesulfon‐amide 2. The N‐[(Z)‐2‐amino‐1,2‐dicycanovinyl carbamoyl]‐p‐toluenesulfonamide 2 was reacted readily with two molar amount of p‐nitrobenzaldehyde at room temperature in the presence of base to give 7,8‐dihy‐dro‐2‐(4‐nitrophenyl)‐8‐oxo‐9‐tosylpurine‐6‐carboxamide 8. Thiation of compounds 3 and 8 using Lawesson's reagent in tetrahydrofuran gave novel thioimidazoles 4, 5, and 6 and thiopurines 9, 10, and 11, which have been characterized spectroscopically.

A convenient synthesis and molecular modeling study of novel purine and pyrimidine derivatives as CDK2/cyclin A3 inhibitors

“…Compounds 10 and 11 were versatile precursors for fused nitrogen heterocycles, especially purine 8 or thiopurine ring. 7 The formation of 11 can be envisaged through the mechanism described by Ernst Schaumann et al 32 and us, 7 The mechanism illustrated that compound 11 is afforded via rearrangement upon base catalyzed cyclization, as outlined in Scheme 2.…”

“…[1][2][3][4][5][6] During the course of our investigations on the use of DAMN in heterocyclic synthesis, we have designed new approaches to 4-cyano-1,3-dihydro-2-oxo-2H-imidazole-5-(N 1 -tosyl)carboxamide 11 (Scheme 1) as a reactive precursor of thiopurine. 7 In some of these cases, new DAMN derivatives and N-({[(Z)-2-amino-1,2-dicyanovinyl]-amino}carbonyl)-4-methylbenzenesulfonamide 10, were used as key intermediates and we give herein a report on these compounds in more detail. Recently, there has been described various natural manifestations of purine systems, that is, methylated, higher-alkylated, and glycosylated forms.…”