Alcohols chlorinative opening

SCHEME 43.16. Carreira et al. s chlorinative opening of epoxy alcohols. 

Substitution of an additional nitrogen atom onto the three-carbon side chain also serves to suppress tranquilizing activity at the expense of antispasmodic activity. Reaction of phenothia zine with epichlorohydrin by means of sodium hydride gives the epoxide 121. It should be noted that, even if initial attack in this reaction is on the epoxide, the alkoxide ion that would result from this nucleophilic addition can readily displace the adjacent chlorine to give the observed product. Opening of the oxirane with dimethylamine proceeds at the terminal position to afford the amino alcohol, 122. The amino alcohol is then converted to the halide (123). A displacement reaction with dimethylamine gives aminopromazine (124). ... 

Phosphazene polymers can act as biomaterials in several different ways [401, 402,407]. What is important in the consideration of skeletal properties is that the -P=N- backbone can be considered as an extremely stable substrate when fluorinated alcohols [399,457] or phenoxy [172] substituents are used in the substitution process of the chlorine atoms of (NPCl2)n> but it becomes highly hydrolytically unstable when simple amino acid [464] or imidazole [405-407] derivatives are attached to the phosphorus. In this case, an extraordinary demolition reaction of the polymer chain takes place under mild hydrolytic conditions transforming skeletal nitrogen and phosphorus into ammonium salts and phosphates, respectively [405-407,464]. This opens wide perspectives in biomedical sciences for the utilization of these materials, for instance, as drug delivery systems [213,401,405,406,464] and bioerodible substrates [403,404]. 

The 8-methyl-8,14-cycloberbine 364, derived from the protoberberine 324 via the betaine 363, was reduced with sodium borohydride or lithium aluminum tri-tert-butoxyhydride to give a diastereoisomeric mixture of cis-and trans-alcohols (7.8 1 or 1 7.8, respectively) (Scheme 64).t)n exposure to formaldehyde the mixture underwent N-hydroxymethylation and subsequent intramolecular substitution on the aziridine ring to give the oxazolidine 365. Removal of the hydroxyl group in 365 was accomplished by chlorination followed by hydrogenolysis with tributyltin hydride. Reductive opening of the oxazolidine 366 with sodium cyanoborohydride afforded ( )-raddeanamine (360), which has already been converted to ochotensimine (282) by dehydration. 

The earliest reported ring-opening polymerizations of functionalized norbornenes were carried out in protic solvents (alcohol, water) using iridium, ruthenium, or osmium salts. Thus, norbornenes substituted with ester (93-95), hydroxy (95), chlorine (96), alkoxy (97), and imide (93) groups have been polymerized via metathesis using noble metal catalysts. 

Next to the above presented use of SiCl for the in situ preparation of a Lewis acid catalyst with a Lewis base for the aldol reaction, it is possible to apply this compound as a reagent in the ring opening of epoxides leading to chlorinated alcohols. Denmark [104] reported that the chiral phosphoramide 38 catalyzed the asymmetric ring opening reaction of meso-epoxides in the presence of tetrachlo-rosilane. Similar examples were provided by Hashimoto in 2002 [105], applying the A -oxide 39 as catalyst (Scheme 30). 

Amyl alcohols can be prepd either from fusel oil or by a synthetic method which involves hydrolysis of amyl chloride, which in turn is prepd by the chlorination of a mixt of pentane and isopentane obtained from petroleum. The ale prepd by synthetic method has, according to Ref 5,p 147, the following props d 0.812 to 0.820 20°/20°, boiling range 120 to 130°, n20° 1.409 and fl p(open cup) 113°F(45°)... 

The formation of ferf-butyl ester 54 may be rationalized by N-chlorination of the pyrazolidinone 50 to give N-chloropyrazolidinone 51. 1,4-Dehydrochlorination of intermediate 51 involving ring-opening by bond breaking steps a (steps a alone would lead to acid chloride 52) and concomitant deprotonation h generates the ketene intermediate 53. Addition of the previously formed ferf-butyl alcohol to ketene 53 provides the otherwise not readily available ferf-butyl ester 54 (87%). 

The double bond of methylenecyclopropanes is alkylated by carbonyl compounds in the presence of TiCLt [483]. While the bicyclic methylenecyclopropane in Eq. (199) suffered simple alkylation followed by chlorination to give the product as a single stereoisomer, monocyclic methylenecyclopropanes showed a quite different behavior, including a ring opening reaction to give alcohols with an allyl chloride moiety (Eq. 200). 

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