β-Aroylpropionic acids. Part V. The synthesis of β-aroyl-α-methylpropionic acids, and their conversion into polynuclear compounds

Abstract

4 : 4'-and 2 : d'-Dimethoxydiphenyl condense with succinic anhydride in presence of aluminium chloride to give f3-2-methoxy-!j+-methoxyphenyland b-Cmethoxy-3-o-methoxyphenyl-benzoylpropionic acid, respectively. Condensation of diphenyl and the a h v e derivatives with methylsuccinic anhydride gives two products in each case, Ar*COCH,*CHMe*CO&I and Ar.COCHMe*CH,*CO,H. Two acids of the former type are cyclised to naphthalene derivatives. 4Methoxydiphenyl gives four products, two of each type.Fluorene gives similarly a product of each type, and the a-methyl acid is converted into 3'-methyl-2 : 3-benzofluorene.SEVERAL investigators have reported that condensed plynuclear compounds such as naphthalene (Haworth, , respectively), and some phenolic ethers such as anisole and o-, m-, and P-tolyl methyl ether, condense with methylsuccinic anhydride in presence of aluminium chloride to give only the P-aroyl-a-methylpropionic acid. We have studied in this investigation whether this is true for diphenyl and some of its derivatives and fluorene. The products were always mixtures of the a-and the p-methyl acid, Ar*CO*CH,*CHMeCO,H and Ar-COCHMeCH2-C0,H, in which the former predominated. The structures of the a-methyl acids were deduced from the facts that they were the less soluble isomers (Org. Reactions, 1949, 5, 243) and with an alcoholic solution of salicylaldehyde and dry hydrogen chloride gave precipitates of the coloured py-ryium derivatives (cf. Mitter and De, J . Indian Ckm. Soc., 1939, 16, 199; Desai and Wali, PYOC. Indian A c d . Sci., 1937, 6, A , 135). The other isomers failed to give this reaction.Thus, diphenyl and methylsuccinic anhydride in nitrobenzene gave a mixture of the acids (Ia and b) in the ratio of 12 : 1. The yield of the latter acid increased when nitrobenzene was replaced by s-tetradoroethane. The position of attack on the diphenyl nucleus was elucidated by oxidising both acids to diphenyl4carboxylic acid. (Ib) R1 = H, R* = Me (11)The a-methyl-keto-acid (Ia) was reduced by Clemmensen's method to the butyric acid (11), which was cyclised with phosphoric oxide to the tetralone (111). This was reduced by lithium aluminium hydride to the tetralin (IV), which was dehydrogenated with selenium to 2-methyl-7-phenylnaphthalene (V). 4 : 4'-and 2 : 2'-Dimethoxydiphenyl condensed with succinic anhydride to give the acids (VIc; Ar = P-MeOC,H,, R3 = OMe, R4 = H) and (VIc; Ar = o-MeO*C,H,, R3 = H, Part IV, 4 : 4'-Dimethoxydiphenyl and Succinic Anhydride.-A stirred mixture of 4 : 4'-dimethoxydiphenyl (10 g.), aluminium chloride (13.4 g.), and nitrobenzene (50 ml.) was treated portionwise with a solution of succinic anhydride (5-2 g.) in nitrobenzene (200 ml.), then left overnight. The product was decomposed with ice and hydrochloric acid and treated with benzene, and the organic layer was extracted with sodium carbonate solution (charcoal), which was later acidiiied. The precipitated acid ( 14.6 g. ; m. p. 123-125") was ~-2-methoxy-S-p-mcthoxy~hcnyZbenz~Zpropionic acid (VIc; Ar = p-MeO*C,H,, Rs = OMe, R 4 = H), colo...

Notes: Preparation of 5-Chloro- and 5-Bromo-2-*acetylethyl)benzimidazoles

“…R-H + Me-C-CO• V-vu< ÍH-C> R-CO-CH=CMe-COOH R-CO-CMe=CH-COOH A R-CO-CH2-CHMe-COOH R-CO-CHMe-CH,-COOHAcids of type A were predominant and less soluble (c/. ref 4…”

Notes- Synthesis of 1-Benzylnaphthalenes

“…Authentic 1-benzy¡naphthalene (Ilia).4 This was prepared according to Nenitzescu el al. 3 A mixture of naphthalene (20 g.) and benzyl chloride (6 g.) w-as treated portionwise with aluminum chloride (22 g.) until hydrogen chloride ceased to be evolved. The product was decomposed with 6.V hydrochloric acid and steam distilled.…”

Palladium‐Catalyzed Arylation of α,α‐Disubstituted Arylmethanols via Cleavage of a C—C or a C—H Bond to Give Biaryls.

“…(95:5) as eluent to give 2-methoxy-1-(2-methoxyphenyl)naphthalene2 (117 mg, 89%): mp 91-92 o C;1 H NMR (400 MHz, CDCl 3 ) δ 3.68 (s, 3H), 3.82 (s, 3H),7.06 (d, 1H, J = 8.4 Hz), 7.08 (dt, 1H, J = 1.1, 7.3 Hz), 7.21 (dd, 1H, J = 1.8, 7.3 Hz), 7.28-7.33 (m, 2H), 7.35-7.37 (m, 1H), 7.37 (d, 1H, J = 8.8 Hz), 7.42 (ddd, 1H, J = 1.5, 7.7, 8.1 Hz), 7.79-7.82 (m, 1H), 7.87 (d, 1H, J = 8.8 Hz); 13 C NMR (100 MHz, CDCl 3 ) δ 55.70, 56.95, 111.30, 114.16, 120.54, 122.10, 123.39, 125.23, 125.35, 126.09, 127.82, 128.83, 129.05, 129.06, 132.40, 133.63, 154.24, 157.72; MS m/z 264 (M + ). The product (611 mg, 93%) was also isolated by treatment of the alcohol (2.5 mmol) and the chloride (3 mmol) under the same CDCl 3 ) δ 31.72, 33.70, 74.50, 125.52, 126.52, 126.70, 126.76, 127.08, 127.63, 127.71, 129.82, 130.03, 130.25, 133.13, 137.97, 140.47, 141.27, 142.44, 146.15; HRMS calcd for C 21 H 20 O 288.1514, found 288.1513.…”