Synthesis of Chromen[4,3-b]pyrrolidines by Intramolecular 1,3-Dipolar Cycloadditions of Azomethine Ylides: An Experimental and Computational Assessment of the Origin of Stereocontrol

Azomethine ylides, generated from imine-derived O-cinnamyl or O-crotonyl salicylaldeyde and α-amino acids, undergo intramolecular 1,3-dipolar cycloaddition, leading to chromene[4,3-b]pyrrolidines. Two reaction conditions are used: (a) microwave-assisted heating (200 W, 185 °C) of a neat mixture of reagents, and (b) conventional heating (170 °C) in PEG-400 as solvent. In both cases, a mixture of two epimers at the α-position of the nitrogen atom in the pyrrolidine nucleus was formed through the less energetic endo-approach (B/C ring fusion). In many cases, the formation of the stereoisomer bearing a trans-arrangement into the B/C ring fusion was observed in high proportions. Comprehensive computational and kinetic simulation studies are detailed. An analysis of the stability of transient 1,3-dipoles, followed by an assessment of the intramolecular pathways and kinetics are also reported.

Crash protection systems for handicapped school and transit bus occupants. Volume III: appendices A, B, C and D. Interim report.

National Highway Traffic Safety Administration, Washington, D.C.

Asiatic Art, VII century B.C.-XVIII century A.D., including sculpture in bronze & stone, ceramics, miniatures and textiles.

Exhibition and sale at the American Art Galleries, New York.

The complete confectioner, or, Housekeeper's guide to a simple and speedy method of understanding the whole art of confectionary : the various ways of preserving and candying, dry and liquid, all kinds of fruit, nuts, flowers, herbs, &c. And the method of keeping them fresh and fine all the year round; the different ways of clarifying sugar; with directions for making fruit pastes, bomboons, pastils, compotes, fruit ices, cream ices, marmalades, jellies, jams, cakes, puffs, biscuits, tarts, custards, cheesecakes, sweetmeats, fritters, creams, syllabubs, blanc-mange, flummeries, ornaments for grand entertainments, dragees, syrups of all kinds, nicknacks and trifles for desserts, strong cordials, oils, simple waters, milk punch that will keep 20 years, and all sorts of English wines. Also, the art of making artificial fruit, with the stalks in it, so as to resemble the natural fruit. To which are added, some bills of fare for desserts for private families /

Originally published under title: The compleat confectioner. Cf. Bitting, K.G. Gastronomic bib., p. 190.

Report to the President by the Emergency Board created June 23, 1948 by Executive order 9971 pursuant to Section 10 of the Railway Labor Act : to investigate and report upon a dispute between the Grand Trunk Western Railroad Co., Chesapeake and Ohio Railway Co., Wabash Railroad and the Ann Arbor Railroad Co. and certain of its employees represented by the National Maritime Union of America, N.M.B. cases A-2801, A-2802, A-2803, A-2804, Detroit, Michigan, July 20, 1948.

Signed: Robert G. Simmons, chairman, Thomas F. Gallagher, member, Joseph L. Miller, member.

East and west through fifteen centuries; being a general history from B.C. 44 to A.D. 1453,

No more published.

A B C de l'apiculture; encyclopédie de tout ce qui a rapport à l'abeille, miel, ruches, instruments, plantes mellifères, etc., résultats d'observations et d'expériences de milliers d'apiculteurs, contrôlées ensuite par un travail pratique dans nos propres ruchers.

p. 518-524 advertising.

L.M.B.C. memoirs on typical British marine plants and animals

Mode of access: Internet.

Las leyes de todos los reynos de Castilla abreuiadas y reduzidas en forma de Reportorio decisiuo por la orden del A.B.C. /

Portada a dos tintas con escudo y orla xilográficos.

El A.B.C. de la visión intuitiva ó principios de la visión relativamente á los tamaños /

Contiene: Parte 1º y Parte 2º

The history of Greece from its commencement to the close of the independence of the Greek nation;

The translators of v. 1-3 are not known; v. 4 was translated by Frederick Clarke, who revised the translation of v. 1-3.

The Roman empire : B. C. 29-A. D. 476 /

Includes index.

Refranes, y modos de hablar castellanos : con los latinos que les corresponden, y la glosa, y explicación de los que tienen necesidad de ella : Con un indice de los adgios latinos, á los quales corresponden los castellanos, que van puestos en el libro por el órden de A. B. C. /

Palau,

The homosexual in literature; a chronological bibliography, circa 700 B.C.-1958,

Cover title.

De elegantia Caesaris, sive, De commentarium de b. G. et de b. c. differentiis animadersiones ...

"Vita."