2-(2-aminophenyl)-acetaldehyde dimethyl acetal: A novel reagent for the protection of carboxylic acids

Tetrahedron Letters

Volumn 39, Issue 1-2, 1998, Pages 71-74

  Arai, Eri ^a   Tokuyama, Hidetoshi ^a   Linsell, Martin S ^b   Fukuyama, Tohru ^a  

^a UNIVERSITY OF TOKYO   (Japan)

^b RICE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

2 (2 AMINOPHENYL) ACETALDEHYDE DIMETHYL ACETAL; ACETAL DERIVATIVE; CARBOXYLIC ACID; UNCLASSIFIED DRUG;

ARTICLE; CHEMICAL REACTION; CHEMICAL STRUCTURE; HYDROLYSIS; ORGANIC CHEMISTRY; REACTION ANALYSIS; SYNTHESIS;

EID: 0031962821     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(97)10491-9     Document Type: Article

References (7)

1. For general references on protective groups, see: Green, T.W.; Wuts, P.G.M. Protective Groups in Organic Synthesis; John Wiley and Sons: New York, 1991.
2. For protection of carboxylic acid as N-acyl indoline and deprotection via indolylamide, see: de Oliveira Baptista, M.J.V.; Barrett, A.G.M.; Barton, D.H.R.; Girijavallabhan, M.; Jennings, R.C.; Kelly, J.; Papadimitriou, V.J.; Turner, J.V.; Usher, N.A. J. Chem. Soc., Perkin Trans 1 1977, 1477. Barrett reported that ozonolysis of amide derivative of 2-allylaniline and subsequent acid treatment led to indolylamide, which can be converted to indole and carboxylic acid. Barrett, A.G.M.; Dhanak, D. Tetrahedron Lett. 1987, 28, 3327.
3. For protection of carboxylic acid as N-acyl indoline and deprotection via indolylamide, see: de Oliveira Baptista, M.J.V.; Barrett, A.G.M.; Barton, D.H.R.; Girijavallabhan, M.; Jennings, R.C.; Kelly, J.; Papadimitriou, V.J.; Turner, J.V.; Usher, N.A. J. Chem. Soc., Perkin Trans 1 1977, 1477. Barrett reported that ozonolysis of amide derivative of 2-allylaniline and subsequent acid treatment led to indolylamide, which can be converted to indole and carboxylic acid. Barrett, A.G.M.; Dhanak, D. Tetrahedron Lett. 1987, 28, 3327.
4. (a) Noland, W.E.; Sellstedt, J.H. J. Org. Chem. 1966, 31, 345.
5. (b) Acheson, R.M.; Hunt, P.G.; Littlewood, D.M.; Murrer, B.A.; Rosenberg, H.E. J. Chem. Soc., Perkin Trans. 1 1978, 1117.
6. 3) δ 2.87 (d, J = 5.4 Hz, 2 H), 3.38 (s, 6 H), 4.05 (br s, 2 H), 4.50 (t, J = 5.4 Hz, 1 H), 6.68 (dd, J = 1.0, 8.0 Hz, 1 H), 6.74 (ddd, J = 1.0, 7.4, 7.4 Hz, 1 H), 7.06-7.07 (m, 2 H).
7. Attempts to prepare ketones via indolylamide were unsuccessful. Thus, addition of methyl lithium to indolylamides afforded a ca. 4:1 mixture of methyl ketones and tertiary alcohols. In the case of α-hydroxyl compound 9, however, addition of methyl magnesium bromide led to a clean formation of the isolable hemianinal 10 as a single isomer.