2-Hydroxy-4-chloroacetophenone

Hydroxyacetophenone Azide (called Azido-4-oxy-acetophenone in Ger) HOC6H4COCH2N3, mw 177.16, N 23.72% yel leaflets (from w) mp 136°, sol in the usual solvents except benzene decomposes in boiling w Prepd by heating 4-hydroxy-chloroacetophenone with Na Azide in ale. No explosive props are mentioned Ref Beil 8 [87]... 

Ethane, 1,1 -thiobis[2-chloro- Chlorobenzilate Benzeneacetic acid,4-chloro-.alpha.-(4-chlorophenyl)-.alpha.-hydroxy-,ethyl ester 2-Chloroacetophenone... 

Nucleophilic Reactions.—Attack on Saturated Carbon. Selected examples of the Arbusov reaction include phosphorylation of the chloroacetophenones (1) to give phosphonates, which cyclized to (2) in the presence of acid chlorides,1 formation of the azodiphosphonate (3) from 2,2 -dichloro-2,2 -azopropane,2 3 and the reaction of 2-chloro-3,4-dihydro-3-oxo-2//-l,4-benzothiazine (4) with triethyl phosphite to give the 2-phosphonate (5), which is used as an olefin synthon.8 Bis(trimethylsilyl) trimethylsiloxymethylphosphonite (6) has been synthesized by silylation of hydroxy-methylphosphonous acid, and, as expected, undergoes a normal Arbusov reaction with alkyl halides to give the phosphonates (7).4 This series of reactions, followed by... 

A special case, leading directly to 3-hydroxy-2-aroylbenzofurans or 3-hydroxy-2-acylbenzofurans (238), is the ring closure (NaH) of 2-aroyloxy-aj-chloroacetophenones or 2-acyloxy-tu-chloroacetophen-... 

Rather phase-insensitive Norrish II photoproduct ratios are reported from irradiation of p-chloroacetophenones with a-cyclobutyl, a-cyclopentyl, a-cycloheptyl, a-cyclooctyl, and a-norbonyl groups [282], In each case, the E/C and cyclobutanol photoproduct ratios are nearly the same in neat crystals as measured in benzene or acetonitrile solutions. On this basis, we conclude that the reaction cavity plays a passive role in directing the shape changes of these hydroxy-1,4-biradicals. As long as the initial ketone conformation within the cavity permits -/-hydrogen abstraction (and these ketones may be able to explore many conformations even within their triplet excited state lifetime), the cavity free volume and flexibility allow intramolecular constraints to mandate product yields. 

Yellow 4-hydroxy-2//-l -benzothiopyran-2-thioncs result from the reaction of 2 -chloroacetophenones with CS2 in the presence of NaH. Their IR spectrum shows no carbonyl stretching absorption band. However, treatment of a solution of the thione with concentrated acid results in the precipitation of the pale yellow 2-mercaptothiochromone 271 for which vc=o occurs at 1610-1620 cm-1. Treatment with base and then dilute acid regenerates the thiocou-marin. Both tautomers appear to exist independently of each other (Equation 20) <1987AJC1179>. 

Nierenstein reaction. Formation of omega-chloroacetophenones by reaction of diazomethane in dry ether with aroyl chlorides. Coumaranones are obtained if an ortho-hydroxy group is present. 

The major riot control agents, or aids to arrest , in current use are 2-chlorobenzylidene mal-ononitrile (CS), 1-chloroacetophenone (CN) and capsaicin, N -(4-hydroxy-3-methoxybenzy l)-8-methyl-6-nonenamide (or pepper spray) the potent and persistent irritant dibenz[b,f]l 4-oxazepine (CR) has rarely been used (Olajos... 

Methoxy-6-chloro-3-8-acetamidoethylbenzo[ blthiophen, a potential anti-ovulatory agent, was prepared in the usual way via condensation of 3-hydroxy-4-chloroacetophenone with rhodanine followed by ring-closure of the intermediate 2-mercapto-2-butenic... 

Preparation from 3-hydroxyacetophenone by chlorination of its 2,3-butylene ketal or its ethylene ketal using tert-butyl hypochlorite. The hydrolysis of these chloroketals with concentrated hydrochloric add in tetrahydrofuran-water mixture gave 3-hydroxy-4-chloroacetophenone (94% and 48% yields, respectively) [1859]. 

Also obtained by UV light irradiation of 4-hydroxy-a-chloroacetophenone in ethanol (26%) [2199],... 

Also obtained from 2-hydroxy-5-methyl-a-chloroacetophenone by treatment with zinc powder in acetic acid [2628],... 

Also obtained by reduction of 4-hydroxy-2-methyl-a-chloroacetophenone with zinc dust in aqueous ethanolic acetic acid [2665]. 

Also obtained (by-product) by reaction of zinc powder and silver chloride on 2-hydroxy-4-methoxy-a-chloroacetophenone in benzene and crotonaldehyde mixture at 60-70° [2745],... 

Also obtained from 4-hydroxy-3-methoxy-a-bromoacetophenone [2801] or 4-hydroxy-3-methoxy-a-chloroacetophenone [2802] by rednctive removal of the halogen atom with iron filings and 10% sulfnric acid in aqneons etlianol at 60°. 

Also obtained by treatment of 2-hydroxy-5-memyl-a-chloroacetophenone with zmc powder and hydrochloric acid [4141],... 

Preparation by reaction of 4-hydroxy-3,5-dime-thyl-a-chloroacetophenone in boiling methylene chloride with 46-48% aqueous hydrobromic acid in the presence of tetrabutylammonium bromide (0.3 M relative to the ketone) for 24 h, (87% yield) [4498]. 

Obtained by reaction of gaseous hydrochloric acid on 5-amino-2-hydroxy-a-chloroacetophenone in ethyl ether [4555]. m.p. 210° (d) [4555]. 

Preparation by hydrolysis of 3-hydroxy-4-methyl-thio-a-chloroacetophenone chloroacetate with 1 N sodium hydroxide in methanol at r.t. (94%) [4627]. 

Obtained by treatment of 2-hydroxy-4,6-dime-thoxy-a-chloroacetophenone with alnmininm chloride in refluxing chlorobenzene for 1 h (85%) [4640]. 

HOs. k COCH2l - Preparation by reaction of sodium iodide on 2,3,4-tri-y ij hydroxy-a-chloroacetophenone in acetone at r.t. 

Preparation by adding a solution of sodium acetate in aqueous acetic acid to an ethanolic solution of 3,4-di-hydroxy-a-chloroacetophenone, and heating at reflux COCH2OCOCH3 for 24 h (83%) [5142]. 

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