372187-64-9Relevant academic research and scientific papers
Facile N-Derivatization of α-Amino Esters and Amides via Benzotriazolylmethyl Derivatives
Katritzky, Alan R.,Kirichenko, Nataliya,Rogovoy, Boris V.,He, Hai-Ying
, p. 9088 - 9092 (2007/10/03)
α-(N-Substituted amino)esters were prepared in a two-step procedure from available unsubstituted α-amino esters. α-Amino esters are first converted into the corresponding N-benzotriazolylmethyl derivatives; in the second step, the benzotriazole group is substituted by various nucleophiles with or without the presence of a Lewis acid to give substituted α-amino esters in high overall yield under mild conditions with no signs of racemization. Boc-protected amino acids were converted into α-amino amides; subsequent deprotection allowed the conversion into N-substituted derivatives analogously to the α-amino esters, without racemization in high yields under mild conditions.
Syntheses of optically active tetrahydro-1H-pyrrolo[1,2-a]imidazol-2-ones and hexahydroimidazo[1,2-a]pyridin-2(3H)-ones
Katritzky, Alan R.,He, Hai-Ying,Wang, Jing
, p. 4951 - 4956 (2007/10/03)
The reactions of (2S)-2-amino-2-substituted-N-(4-nitrophenyl)acetamides 16a-c, succindialdehyde (13), and benzotriazole afforded enantiopure (3S,5R,7aR)-5-(1H-1,2,3-benzotriazol-1-yl)-3-substituted-1-(4-nitrophenyl) tetrahydro-1H-pyrrolo[1,2-a]imidazol-2-ones 17a-c, which were converted by sodium borohydride into (3S,7aR)-3-substituted-1-(4-nitrophenyl)tetrahydro-1H-pyrrolo[1, 2-a]imidazol-2-ones 18a-c. Chiral (2S)-2-amino-2-substituted-N-(4-methylphenyl)acetamides 12a-d, easily prepared in two steps from N-Boc-α-amino acids 10a-d, similarly reacted with glutaraldehyde (20) and benzotriazole to generate 5-benzotriazolyl-3-substituted-hexahydroimidazo[1,2-a]pyridin 2(3H)-ones 21a-d, which were converted by sodium borohydride directly into optically active 3-substituted-hexahydroimidazo[1,2-a]pyridin-2(3H)-ones 22a-d.
Stereoselective syntheses of chiral (3S,9bS)-1,2,3,9b-tetrahydro-5H-imidazo[2,1-a]isoindol-5-ones
Katritzky, Alan R.,He, Hai-Ying,Verma, Akhilesh K.
, p. 933 - 938 (2007/10/03)
Chiral (3S,9bS)-1,2,3,9b-tetrahydro-5H-imidazo[2,1-a]isoindol-5-ones 11a-11f, 14b,14c and 17a,b were prepared in 78-93% yields with high stereoselectivities (d.e. >99%) by the intermolecular condensations of 2-formylbenzoic acids 10 or 13 or 2-acetylbenzoic acid 15 with chiral diamines 9a-9f and 9h. Compounds 9a-9f and 9h were readily prepared in three steps from optically active N-Boc-α-amino acids 5a-5d.
Convenient syntheses of unsymmetrical imidazolidines
Katritzky, Alan R.,Suzuki, Kazuyuki,He, Hai-Ying
, p. 3109 - 3114 (2007/10/03)
Unsymmetrical imidazolidines 10-14, optically active imidazolidines 20-22, and 2,3-dihydro-1H benzimidazoles 28 and 29 were synthesized in good to excellent yields by Mannich reactions of 1,2-ethanediamines 8a-c, 18a-c, or N-methyl-1,2-benzenediamine (26a) with benzotriazole and formaldehyde, followed by the nucleophilic substitution of the benzotriazolyl group with C- nucleophiles (Grignard reagents, sodium cyanide), an S-nucleophile (benzenethiol), and a P-nucleophile (triethyl phosphite).
Stereoselective syntheses of 1H-imidazo[2,1-a]isoindole-2,5(3H,9bH)-diones
Katritzky,Xu,He,Steel
, p. 1767 - 1770 (2007/10/03)
1H-Imidazo[2,1-a]isoindole-2,5(3H,9bH)-diones 6a-i are synthesized in 67-96% yields with high stereoselectivities (de 88-99%, except 6e with a 58% de value) via intermolecular condensation of 2-formylbenzoic acid (5) and α-amino amides 4a-i in the presence of a catalytic amount of toluene-p-sulfonic acid. Intermediates 4 are obtained in two steps from easily available chiral N-Boc-α-amino acids 1.
