By Author Unknown
Read Online or Download Advances in Heterocycling Chemistry. Vol. 44 PDF
Similar chemistry books
Content material: Rüchardt, C. Steric results in unfastened radical chemistry. -- Birkofer, L. and Stuhl, O. Silylated synthons. -- Muszkat, ok. A. The 4a, 4b-dihydrophenanthrenes. -- Anh, N. T. Regio- and stereo-selectives in a few nucleophulic reactions
Substitute solvents - together with supercritical fluids and room temperature ionic drinks - shape a good portion of study in eco-friendly chemistry. Solvents are vital in analytical chemistry, product purification, extraction and separation applied sciences, and in addition within the amendment of fabrics.
- Coordination Compounds - Synthesis and Medical Application
- Chasing Molecules Poisonous Products, Human Hromise of Green Chemistry -
- Inorganic Chemistry of the Transition Elements: v. 3: A Review of Chemical Literature (Specialist Periodical Reports)
- The Chemistry of Allelopathy. Biochemical Interactions Among Plants
Additional info for Advances in Heterocycling Chemistry. Vol. 44
The geometry of the coordination complex (113) makes addition of the amide ion at C-2 attractive. Conditions needed to generate a diamino derivative are typically harsher than those required for monoamination. A Japanese patent cites the preparation of 2,6-diamino-4-propylpyridine (I 15) from 4-propylpyridine (114) with excess sodium amide in Tetralin at 145-195°C (Scheme 45) (80JAP(K)76861). n-Pr n-Pr NH, SCHEME 46 Sec. B] ADVANCES IN THE CHICHIBABIN REACTION 41 Other pyridine derivatives have been aminated with alkali metal amides.
This argument is weakened by the lack of a kinetic isotope effect in the Chichibabin amination (65CJC725). Alternatively, the amide ion may be attracted to the 2-position by an ion-dipole interaction with the 3-substituent in the addition step. For a substrate like 3-dimethylaminopyridine (1lo), this is a very significant interaction (113), leading exclusively to the 2-amino product (Scheme 44) (73CHE1119). Pyridine rings containing electron-donating substituents are deactivated toward the Chichibabin reaction relative to pyridine.
Amination of 5-bromo- 1,7-naphthyridine with potassium amide in liquid ammonia gave a small yield of a normal Chichibabin product, 8-amino-5bromo- 1,7-naphthyridine, along with tele-aminated products 8-amino- and 2amino-l,7-naphthyridine. 5-Chloro-l,7-naphthyridine(202) gave a low yield of 8-amino-5-chloro- 1,7-naphthyridine (203)and other unidentified products (Scheme 71) (78JHC731). 56 CHARLES K . McGILL AND ANGELA RAPPA CI [Sec. E CI NaNH, k RI SCHEME 72 E. (82CHE1221). Criteria for successful amination require that the imidazole ring be condensed with an aromatic system at the 4and 5-positions, and that the pyrrole nitrogen be substituted (Scheme 72) (73CHE88).
Advances in Heterocycling Chemistry. Vol. 44 by Author Unknown