Combinatorial solution-phase synthesis of alkyl (1S*,2S*,3R*,5R*,6R*)-1-alkyl-3-aryl-6-benzoylamino-1-hydroxy-7- oxo-5-phenylhexahydropyrazolo[1,2-a]pyrazole-2-carboxylates.
Combinatorial solution-phase cycloadditions of (1Z,4R*,5R*)-4-benzoylamino-5-phenylpyrazolidin-3-on-1-azomethine imines 3 to beta-keto esters 4 afforded a library of 26 bicyclic pyrazolidinones 5 in 6-89% yields and in 14-100% de. All products were isolated in >90% purity according to 1H NMR, and 25 of them were analytically pure. The structures of cycloadducts were confirmed by NMR and X-ray diffraction. Most of the products were isolated as mixtures of the major (1S*,2S*,3R*,5R*,6R*)-epimers 5 and the minor (1R*,2S*,3R*,5R*,6R*)-epimers 6. Epimerization of cycloadducts 5/6 at the anomeric position 1 in solution was confirmed by 1H NMR.
Pezdirc
Lidija
L
Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, P.O. Box 537, 1000 Ljubljana, Slovenia.
Bevk
David
D
Groselj
Uros
U
Meden
Anton
A
Stanovnik
Branko
B
Svete
Jurij
J
D000478:Alkylation; D000588:Amines / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry; D001554:Benzene / Q000737:chemistry*; D002264:Carboxylic Acids / Q000138:chemical synthesis / Q000737:chemistry*; D004952:Esters / Q000737:chemistry; D006900:Hydroxylation; D007097:Imines / Q000737:chemistry; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry*; D011720:Pyrazoles / Q000737:chemistry*; D012996:Solutions; D013882:Thiosemicarbazones / Q000737:chemistry
D000588:Amines; D001391:Azo Compounds; D002264:Carboxylic Acids; D004952:Esters; D007097:Imines; D011720:Pyrazoles; D012996:Solutions; D013882:Thiosemicarbazones; C512188:azomethine; C031280:pyrazole; D001554:Benzene; D010100:Oxygen