Cyclopropyl→cyclobutyl rearrangement in intramolecular cyclization of 3,5-bridged B-secoandrostane-6,7(or 5,7)-diols and mass spectra of products

1982 ◽  
Vol 47 (8) ◽  
pp. 2280-2290 ◽  
Author(s):  
Helena Velgová ◽  
Jorga Smolíková ◽  
Antonín Trka ◽  
Antonín Vítek
Keyword(s):  
Intramolecular Cyclization ◽  
Mass Spectra ◽  
Acid Catalyzed

Acid-catalyzed intramolecular cyclization of 6,7-dihydroxy-3α,5-cyclo-6,7-seco-5α-androstan-17-one (VII), 5,7-dihydroxy-3,5-methylene-5,7-secoandrostan-17-one and 5,7-dihydroxy-3β,5-cyclo-5,7-seco-A-homo-5β-androstan-17-one (XIII) in benzene and dioxane was investigated. The main cyclization products were 3,5-methylene-6-oxaandrostan-17-one (I) and/or 3β,5-cyclo-6-oxa-A-homo-5β-androstan-17-one (VIII). In the case of VI and VII the ratio of I and VIII was solvent-dependent: in benzene more VIII was formed than in dioxane. The mass spectra of I and VIII were almost identical and corresponded to the structure VIII.

Intramolecular cyclization of N-phenylanthranilic acid catalyzed by MCM-41 with different pore diameters

2015 ◽  
Vol 41 (12) ◽  
pp. 10125-10135 ◽  
Author(s):  
Shangyou Xiao ◽  
Guang Xu ◽  
Gang Chen ◽  
Xiaojing Mu ◽  
Zhitao Chen ◽  
...  
Keyword(s):  
Intramolecular Cyclization ◽  
Acid Catalyzed ◽  
Mcm 41

Acid-catalyzed rearrangements of an A(1)-nor-triterpenoid 2α,3α-epoxide

1989 ◽  
Vol 54 (2) ◽  
pp. 413-429 ◽  
Author(s):  
Jiří Klinot ◽  
Jiří Liška ◽  
Alena Forgáčová ◽  
Miloš Buděšínský ◽  
Jiří Protiva ◽  
...  
Keyword(s):  
Acidic Medium ◽  
Boron Trifluoride ◽  
Mass Spectra ◽  
Boron Trifluoride Etherate ◽  
Methyl Group ◽  
Unsaturated Alcohols ◽  
Acid Catalyzed ◽  
C Nmr

Reactions of 2α,3α-epoxide X, derived from 19β,28-epoxy-A(1)-nor-18α-oleanane, with acids proceed with migration of the 10β-methyl group into the position 2β, giving rise to unsaturated alcohols XII and XIV and diene IX. Reaction with boron trifluoride etherate afforded ketone XI in addition to XII and XIV. Olefin VIII rearranged in acidic medium to give olefins XXVI and XXVII. The rearranged products were converted into other derivatives and their structure was established by 1H and 13C NMR, IR, UV and mass spectra.

scholarly journals Acid-Catalyzed Hydrolysis and Intramolecular Cyclization of N-Cyano Sulfoximines for the Synthesis of Thiadiazine 1-Oxides

ACS Omega ◽  
2022 ◽  
Author(s):  
In Seok Oh ◽  
Ye Ji Seo ◽  
Ji Young Hyun ◽  
Hwan Jung Lim ◽  
Duck-Hyung Lee ◽  
...  
Keyword(s):  
Intramolecular Cyclization ◽  
Acid Catalyzed

Bor-stabilisierte N,O-Carbene, I Triphenylbor-Addukte von Siloxy-und Hydroxyalkylisocyaniden und spontane At-Ylid-Bildung / Boron-Stabilized N.O-Carbenes, I Triphenylboron Adducts of Siloxy- and Hydroxyalkyl Isocyanides and Spontaneous Formation of Ate-Ylids

1989 ◽  
Vol 44 (4) ◽  
pp. 419-428 ◽  
Author(s):  
Wolf Peter Fehlhammer ◽  
Hans Hoffmeister ◽  
Heribert Stolzenberg ◽  
Borislav Boyadjiev
Keyword(s):  
Intramolecular Cyclization ◽  
Mass Spectra ◽  
H Nmr ◽  
Spontaneous Formation ◽  
Stable Species ◽  
Boron Complexes ◽  
New Compounds

.Triphenylboron adducts of 2- and 3-hydroxyalkyl isocyanides spontaneously undergo intramolecular cyclization to give oxazolidin-2-ylidene and perhydrooxazin-2-ylidene boron complexes, respectively. The same compounds are obtained by methanolysis of the stable species Ph3B-CNCR1R2CR3R4-OSiMe3 (R1, R2, R3, R4 = H, alkyl) (2a-i) and Ph3B-CN(CH2)3-OSiMe3 (2j)IR, 1H NMR, 13C{H} NMR. and mass spectra of the new compounds are reported.

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