Experimental and theoretical study of the role of CH/π interactions in the aminolysis reaction of acetyl galactoside

Molecular recognition of saccharides is a growing field, which has many implications in cancer therapy, drug discovery, and cellular communication among others. The participation of CH/p interactions in this event is well known. Nevertheless, the intrinsic role of CH/p for modulating chemical reactions is still far from being applicable. In this experimental and computational work we have evaluated the participation of CH/p interactions in the aminolysis reaction of acetyl galactoside promoted with different 6-substituted 2(1H)-pyridones. Two features have been incorporated to the promoter molecular structure, on one end the promoting pyridone group and on the other end the recognition moiety, joined together by an alkyne spacer. The small increment in the observed pseudo-first-order rate constant values (kobs) was related to the stability of the transition state provided by noncovalent interactions, including CH/p interactions. A longer alkyne spacer was necessary to improve the molecular recognition of the galactoside substrate. The trend of the calculated activation energy values (∆ERTS) was in good accordance with the experimental rate constant values.We thank CONACyT (grants 165614 and 284923) and DGAPA-UNAM (grant IN-209416) for financial support. We thank DGTIC, UNAM, for supercomputer resources (grant SC14-1-I-70). F C-G is grateful to CONACyT for the scholarship granted number 256121. We are grateful to Posgrado en Ciencias Químicas UNAM. We are grateful to QFB. Rocío Patiño-Maya for her support in the use of polarimeter. We are grateful to Dr. Beatriz Quiróz-García, Dr. Nuria Esturau-Escofet, Q. Ángeles Peña-González, MSc. Elizabeth Huerta-Salazar and Dr. Isabel Chávez-Uribe for the technical assistance in NMR spectroscopy. We are grateful to IQ. Luis Velasco-Ibarra and Dr. Francisco J. Pérez-Flores for the technical assistance in mass spectrometry. We are grateful to Dr. José E. Barquera-Lozada and MSc. Lydia Ledezma-Olvera for providing the computational facilities to perform calculations with AIMAll software and for important discussions. We are grateful to Dr. Victor Duarte-Alaniz for the making of Figures 5 to 8 produced with Rhorix on Blender