Synthesis of 1,2,4,5,7,8-hexaoxonanes by iodine-catalyzed reactions of bis(1-hydroperoxycycloalkyl) peroxides with ketals

Iodine-catalyzed reactions of bis(1-hydroperoxycycloalkyl) peroxides with ketals give, via replacement of two alkoxy groups, the cyclic peroxides, 1,2,4,5,7,8-hexaoxonanes, in up to 82% yields. The cyclization is very sensitive to the solvent nature. Among MeCN, Et₂O, THF, CHCl₃, CH₂Cl₂, hexane, and MeOH, the best results were achieved with the first three solvents.     

First synthesis of cyclic organogermanium peroxides, 1,2,4,5,7,8-hexaoxa-3-germonanes

First, previously unknown, cyclic organogermanium peroxides, 1,2,4,5,7,8-hexaoxa-3-germonanes, were synthesized by the reaction of 1,1′-dihydroperoxydi(cyclododecyl)peroxide with (di)alkyl(aryl)dihalogengermanes. The new compounds have a higher tendency to undergo hydrolysis compared to silicon-containing analogs.     

New preparation of α-allenic ketones

The ketal aldehyde 2 is the starting material of a two-step synthesis of α-allenic ketones 1 γ-substituted with a functionalized chain.     

New method for preparation of 2-bromothiophene

Conclusions The reaction of KBrO₃ with thiophene in the presence of HBr in a two-phase water-ether system permits obtaining 2-bromothiophene, not contaminated with 2,5-dibromothiophene, in high yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2388–2389, October, 1982.     

3,3,6,6,9,9‐Hexaethyl‐1,2,4,5,7,8‐hexaoxacyclononane at 296 K

The title molecule (diethyl ketone triperoxide, DEKTP), C₁₅H₃₀O₆, is a cyclic triperoxide closely related to triacetone triperoxide (TATP), one of the most unstable explosives known. However, the stability of DEKTP is ca 20–50 times greater than that of TATP. DEKTP crystallizes with two molecules in the asymmetric unit, with virtually identical geometry. The cyclononane core is stabilized in a twisted boat–chair conformation (approximate D₃ symmetry), very close to that previously described for TATP. The explanation for the safe thermal behaviour of DEKTP compared with TATP should thus not be sought in the molecular dimensions, but rather in the thermal decomposition kinetics.     

New synthesis route for the preparation of pomalidomide

A new route for the preparation of pomalidomide is described in the study. The synthetic procedure starts from 4-nitroisobenzofuran-1,3-dione and 3-aminopiperidine-2,6-dione hydrochloride via a three-step reaction resulting in a total yield of 65% with a high-performance liquid chromatographic (HPLC) purity of 99.56% and a low palladium residue level of 2 ppm. This method can be deemed as an efficient, practical, and environmentally friendly synthetic route for the preparation of pomalidomide.     

New method for the preparation of condensed imidazolones

Condensed imidazolones were obtained by the action of diethyl pyrocarbonate on aromatic o-diamines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1277–1280, September, 1976.     

New method for the preparation of t-butyldimethylsilyl triflate

t-Butyldimethylsily triflate is easily prepared from the reaction of triflic acid with isopropenyltrimethylsilane.     

New reaction for the preparation of liquid rubber

The article reports on the noncatalytic transformation of a polybutadiene (number‐average molecular weight = 128,000) into a functionalized liquid rubber via the carboxidation of the polymer C?C bonds by nitrous oxide. The reaction was conducted in a benzene solution at 160–230 °C and a pressure of 3–6 MPa. The carboxidation mechanism was determined. The main route (95%) of the reaction proceeded without cleavage of C?C bonds and led to the formation of ketone groups in the polymer backbone. A minor route (5%) of the reaction proceeded with the cleavage of C?C bonds, yielding two smaller fragments containing aldehyde and vinyl end groups. The availability of the cleavage route could lead to a dramatic decrease in the molecular weight, which, depending on the carboxidation degree, could be 1–2 orders of magnitude less than that of the initial material. Thus, the carboxidation of more than 15% of the polybutadiene C?C bonds transformed it into a C?O‐functionalized liquid rubber with a narrow molecular weight distribution. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2510–2520, 2006     

New process for the preparation of methyl carbonates

The methyl carbonate of HOBt was developed for the conversion of alcohols to carbonates. This method is superior to the use of methyl chloroformate or methyl pyrocarbonate, especially with more hindered alcohols. The reagent is a stable solid that is easily prepared on a multigram scale. [reaction: see text]