Laser-powered decomposition of spiro[2.n]alkanes (n = 2-5)
摘要:
The laser heating of spiro[2.n]alkanes (n = 2-5) and of their 1,1,2,2-tetradeuterated isotopomers reveals dissimilar modes of their thermal decomposition. Spiropentane decomposes into ethene and propadiene via two competing routes: the direct cleavage and the more important cleavage via intermediary methylenecyclobutane. Spirohexane decomposes through two important concurrent pathways which are the expulsions of ethene from the three-membered ring and a more feasible expulsion of ethene from the four-membered ring. Spiroheptane and spirooctane decompose by a radical-chain mechanism and afford complex mixtures of products; upon addition of propene both compounds rearrange into two cycloalkanes wherein the larger ring of the spiroalkane is preserved and substituted with ethylidene and a vinyl group.
The invention relates to 1,1-disubstituted cyclohexane derivatives containing one or more polymerisable groups, and to liquid-crystalline media comprising at least one compound of the formula I. At least one of the polymerisable groups is located at the geminally substituted position of the cyclohexane ring. The compounds are suitable for the stabilisation of liquid-crystalline phases. Examples of polymer-stabilised blue phases are indicated.
NORBORNENE-TYPE POLYMERS HAVING QUATERNARY AMMONIUM FUNCTIONALITY
申请人:Bell Andrew
公开号:US20110143260A1
公开(公告)日:2011-06-16
Embodiments of the present disclosure encompass vinyl addition and ROMP polymers having at least one type of repeating unit that encompasses a comprise N
+
(CH
3
)
3
OH
−
moiety. Other embodiments in accordance with the disclosure include alkali anion-exchange membranes (AAEMs) made from one of such polymers, anion fuel cells (AFCs) that encompass such AAEMs and components of such AFCs, other than the AAEM, that encompass one of such polymers.
Omega-[(hetero)alkyl]benz[cd]indol-2-amines useful in inhibition of thromboxane synthetase and in treatment of hypertension in warm-blooded animals are disclosed.
Access to 3‐Azetidines via Halogenation of Titanacyclobutanes
作者:Tyler D. Weinhold、James A. Law、James H. Frederich
DOI:10.1002/adsc.202301527
日期:2024.5.21
Azetidines are valuable nitrogenous heterocycles. Herein, we disclose a strategy for the modular assembly of 3‐azetidines and related spirocyclic congeners featuring all‐carbon quaternary centers. This approach leverages titanacyclobutanes generated from ketones or alkenes. Halogenation of these organotitanium species gives rise to functionalized alkyl dihalides that can be subsequently captured by