Tris(pentafluorophenyl)borane‐Catalyzed Oxygen Insertion Reaction of α‐Diazoesters (α‐Diazoamides) with Dimethyl Sulfoxide

Author(s):  
xiao-yang wu ◽  
Wenxia Gao ◽  
Yun-Bing Zhou ◽  
Miaochang Liu ◽  
Huayue Wu
2020 ◽  
Vol 56 (23) ◽  
pp. 3453-3456 ◽  
Author(s):  
Pranesh Pal ◽  
Prathama S. Mainkar ◽  
Kiranmai Nayani ◽  
Srivari Chandrasekhar

An efficient cascade radical addition/cyclization/oxygen insertion reaction of alkyne-tethered cyclohexadienones with TMSN3 was carried out under mild conditions to generate bicyclic azido alcohol scaffolds.


2016 ◽  
Vol 52 (40) ◽  
pp. 6658-6661 ◽  
Author(s):  
Sam Yruegas ◽  
Dayna C. Patterson ◽  
Caleb D. Martin

The synthesis of 1,2-oxaborines is accomplishedviathe reaction of pentaarylboroles withN-methylmorpholine-N-oxideviaa 1,1-insertion reaction.


2019 ◽  
Vol 84 (21) ◽  
pp. 14349-14353 ◽  
Author(s):  
Muhammad Kazim ◽  
Hayden Foy ◽  
Maxime A. Siegler ◽  
Travis Dudding ◽  
Thomas Lectka

1965 ◽  
Vol 87 (14) ◽  
pp. 3273-3273 ◽  
Author(s):  
Ruth F. Nutt ◽  
Byron Arison ◽  
Frederick W. Holly ◽  
Edward Walton

1975 ◽  
Vol 152 (2) ◽  
pp. 233-241 ◽  
Author(s):  
Roger E. Cripps

1. An organism that utilizes acetophenone as sole source of carbon and energy was isolated in pure culture and tentatively identified as an Arthrobacter sp. 2. Cell-free extracts of the acetophenone-grown organism contained an enzyme, acetophenone oxygenase, that catalysed an NADPH-dependent consumption of O2 in the presence of the growth substrate; approx. 1mol of O2 and 1mol of NADPH were consumed per mol of acetophenone oxidized. 3. Cell-free extracts also contained an enzyme capable of the hydrolysis of phenyl acetate to phenol and acetate. The amount of this esterase was increased markedly by growth on acetophenone. 4. The observed products of the acetophenone oxygenase reaction by crude cell-free extracts were phenol and acetate. However, inhibition of the phenyl acetate esterase by paraoxon resulted in the formation of phenyl acetate from acetophenone. 5. A degradative sequence is proposed in which acetophenone is metabolized by an oxygen-insertion reaction to form phenyl acetate. Further metabolism occurs by hydrolysis of this ester. 6. The organism and extracts were shown to metabolize chlorinated acetophenones. The environmental implications of this observation are discussed.


1976 ◽  
Vol 36 (01) ◽  
pp. 221-229 ◽  
Author(s):  
Charles A. Schiffer ◽  
Caroline L. Whitaker ◽  
Morton Schmukler ◽  
Joseph Aisner ◽  
Steven L. Hilbert

SummaryAlthough dimethyl sulfoxide (DMSO) has been used extensively as a cryopreservative for platelets there are few studies dealing with the effect of DMSO on platelet function. Using techniques similar to those employed in platelet cryopreservation platelets were incubated with final concentrations of 2-10% DMSO at 25° C. After exposure to 5 and 10% DMSO platelets remained discoid and electron micrographs revealed no structural abnormalities. There was no significant change in platelet count. In terms of injury to platelet membranes, there was no increased availability of platelet factor-3 or leakage of nucleotides, 5 hydroxytryptamine (5HT) or glycosidases with final DMSO concentrations of 2.5, 5 and 10% DMSO. Thrombin stimulated nucleotide and 5HT release was reduced by 10% DMSO. Impairment of thrombin induced glycosidase release was noted at lower DMSO concentrations and was dose related. Similarly, aggregation to ADP was progressively impaired at DMSO concentrations from 1-5% and was dose related. After the platelets exposed to DMSO were washed, however, aggregation and release returned to control values. Platelet aggregation by epinephrine was also inhibited by DMSO and this could not be corrected by washing the platelets. DMSO-plasma solutions are hypertonic but only minimal increases in platelet volume (at 10% DMSO) could be detected. Shrinkage of platelets was seen with hypertonic solutions of sodium chloride or sucrose suggesting that the rapid transmembrane passage of DMSO prevented significant shifts of water. These studies demonstrate that there are minimal irreversible alterations in in vitro platelet function after short-term exposure to DMSO.


1964 ◽  
Vol 11 (01) ◽  
pp. 222-229 ◽  
Author(s):  
Isaac Djerassi ◽  
Albert Roy ◽  
Jorge Alvarado ◽  

SummaryHuman platelets frozen at −195° C (liquid nitrogen) retain their morphological integrity and ability to promote clot retraction when 5% dimethyl-sulfoxide and 5% dextrose are added to the suspending plasma medium. Slow freezing was more effective than direct immersion in the liquid nitrogen. Although similar results may be achieved with dimethylsulfoxide alone with rigidly controlled freezing rates, the addition of sugars may permit freezing under less critical conditions.Dimethylsulfoxyd und 5% Dextrose dem Plasmamilieu hinzugefügt werden. Das langsame Einfrieren ist effektiver als das direkte Eintauchen in flüssigen Stickstoff. Obschon ähnliche Resultate mit Dimethylsulfoxyd allein unter exakter Kontrolle der Einfrierungsgeschwindig-keit erreicht werden können, erlaubt die Zugabe von Dextrose ein Einfrieren unter weniger kritischen Bedingungen.


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