2011年10月5日 · In summary, lactol 1′/1″ is a model of very stable cyclic hemiacetalic forms of hydroxy-aldehydes. Their derivatives, with CH CH–EWG instead of CH O, show a similar strong tendency to form stable oxolanes (THF derivatives as very major products). If these are required, as happens in many cases, even in the total synthesis of several ...

2011年3月14日 · With lactol 71b in hand, the glycosylation was examined. Traditional methods for glycosylation of iridoid aglycones proceed via the acetylated lactol; however, in 2009 Krische 24 and coworkers reported the direct glycosylation of lactol 72 utilizing the trichloroacetimidate glycosyl donor 73 (Scheme 17, Equation 5). 33 As this had the potential to remove a synthetic operation, glycosylation of ...

2004年12月13日 · Thus, the lactol 14 reacted with Ph 3 P:CHCO 2 Me in refluxing acetonitrile to form an intermediate enoate (not shown in the Scheme), which then underwent a spontaneous Michael ring closure, affording a mixture of α- and β-C-glycosides 15 20 and 16 21 in a …

2019年1月1日 · Lactitol is a multipurpose ingredient with various applications in the food, dairy, and pharmaceutical fields.

2021年6月1日 · The lactol structures were all confirmed with 1 H, 13 C, HMBC and HSQC NMR (see ESI). Conclusion In conclusion we have developed a new highly efficient copper(I) catalyst for the selective aerobic oxidation of aliphatic, allylic and benzylic primary alcohols to their corresponding aldehydes in high yields.

1984年1月25日 · THE JOURNAL OF BIOLOGICAL CHEMISTRY 0 1984 by The American Society of Biological Chemists, Inc. Vol. 259, No. 2, Issue of January 25, pp. W-889, 1984 Printed in U S A Isolation, Identification, and Metabolism of (23S,25R)-25- Hydroxyvitamin D3 26,23-Lactol A BIOSYNTHETIC PRECURSOR OF (23S,25R)-25-HYDROXYVITAMIN D3 26,23-LACTONE* (Received for publication, March 25, 1983) Sachiko Yamada, Keiko ...

2019年8月30日 · Open and lactol forms of P450 11B2 products. 18-OH corticosterone can exist in either the keto or hemiketal (lactol) form. Aldosterone can exist in the aldo, hemiacetal (lactol), or acetal (lactol) form. The position of the final oxidation catalyzed by P450 11B2 is the C18 position and is noted in red. Download : Download high-res image (56KB)

1998年9月3日 · Pergamon Tetrahedron 54 (1998) 10691-10698 TETRAHEDRON The ortho-Hydroxy-ortho'-Formyl Biaryl / Lactol Equilibrium: Quantumchemical Studies on Structure and DynamicsI Gerhard Bringmann*, Daniel Vitt, Jiirgen Kraus and Matthias Breuning Institut ftir Organische Chemic, Universit~it Wtirzburg, Am Hubland, D-97074 Wfirzburg, Germany Received 5 March 1998; revised 10 June 1998; accepted 19 June ...

2011年7月22日 · A stereoselective approach to the γ-lactol moiety of halichoblelide is described starting from commercially available (R)-3-butyn-2-ol. The key step is the hydroboration of a chiral protected 1,2-butadien-3-ol and its addition to furfural.

2007年11月16日 · During biotransformation of diol 2a the concentration of lactol 2b was nearly constant and decreased finally when 2a vanished. After 4 h a transient maximum of lactone 2c was reached, however, after 16 h also 2c was completely consumed (data not shown). We propose that lactols are formed from diols by oxidation of the primary hydroxyl group ...