Efficient and Facile Glycol Cleavage Oxidation Using Improved Silica Gel-Supported Sodium Metaperiodate

Synthesis of Novel Purinyl-1'-homocarbanucleosides Based on a Cyclopenta[b]pyrazine System

“…Oxidative cleavage of 10 with sodium periodate on silica gel 17) then gave dialdehyde 11 (as identified by IR spectroscopy), and reduction of crude 11 with NaBH 4 in methanol finally afforded an approximately 2 : 1 mixture of the desired cis-diol 12 and its diastereomer 13; partial epimerization is presumed to have occurred during these last two steps.…”

A β-lactam route to short peptide segments related to angiotensin-converting enzyme (ACE) inhibitors

“…To this end, the β-lactam 7 was transformed into the NCA 8 in 95% yield by treatment with a solution of commercial bleach and a catalytic amount of 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO). Then, the coupling reaction of this NCA with three representative nucleophiles in methylene chloride (mol ratio of 8 to nucleophile 1:2) was carried out, and the isomerization degree for each reaction was determined by 13 C NMR. The coupling reactions with benzylamine and aniline gave 9a and 9b, along with the corresponding epimers, in ratios of 87:13 and 90:10, respectively.…”

“…The aqueous phase was separated and extracted with diethyl ether (2 x 20 ml). The combined organic layer was dried over MgSO 4 and the solvent was evaporated under reduced pressure to give the title compound which was purified by column chromatography (silica gel, ethyl acetate:hexane 1:2 as eluent 13 C NMR (CDCl 3 , δ) 170. 8,169.6,141.3,128.3,128.2,126,75.7,59.2,52.1,49.6,31.8,30.9,16.6;Anal.…”

“…HCH), 2.62 (m, 1H, HCH), 2.29-1.91 (m, 6H, 3CH 2 ), 1.38 (d, 3H, J=7.2 Hz, HCCH 3 ); 13 C NMR (CDCl 3 , δ) 172, 169.5,169.3,142.1,136.0,129.0,128.9,128.8,128.7,128.6,126.5,76.3,67.4,60.7,59.3,48.5,47.4,32.4,31.7,29.3,25.3,16.9. Anal.…”

Asymmetric Synthesis and Absolute Configuration Assignment of a New Type of Bedaquiline Analogue

“…Cleavage of the diol was effectively and conveniently performed by treatment with NaIO4-impregnated silica gel to convert the diol 10a into the aldehyde 11a [24]. The introduction of the third aryl group to form the TARB skeleton was achieved through the attack of 1-naphthylmagnesium bromide to aldehyde 11a, followed by oxidation with DMP to yield the keto compound 13a.…”