Benzyl 1,3-Butadiene-1-carbamate

Abstract

(1; R = Ph) [65899-49-2] C12H13NO2 (MW 203.09) InChI = 1S/C12H13NO2/c1-2-3-9-13-12(14)15-10-11-7-5-4-6-8-11/h2-9H,1,10H2,(H,13,14) InChIKey = LSQDRSXFUSBRBP-UHFFFAOYSA-N (2; R = Me) [61759-61-3] C7H11NO2 (MW 141.08) InChI = 1S/C7H11NO2/c1-3-5-6-8-7(9)10-4-2/h3,5-6H,1,4H2,2H3,(H,8,9) InChIKey = XETZLCYONPVAHN-UHFFFAOYSA-N (1,3-dienes: useful aminobutadiene equivalents for Diels–Alder reaction,1 regio- and stereoselective reactions even with poor dienophiles;2 used in the synthesis of complex heterocyclic natural products3 and aminoanthraquinones4) Physical Data: 5-7 (1) mp 74–75 °C; 1H NMR (CDCl3) δ 7.32 (s, Ph), 6.71 (br d, J = 9 Hz, CHNH), 6.26 (dt, J = 10, 17 Hz, CHCH2), 5.4–5.8 (m, CHCHNH and NH), 5.15 (s, CH2Ph), 4.8–5.2 (m, CH2); 13C NMR (CDCl3) δ 127.2, 112.5, 134.6, 113.5, 128.3, 128.4, 128.7, 136.0, 153.7, 67.5. (2) mp 44–45 °C; 1H NMR (CDCl3) δ 7.7 (br d, NH), 5.3–6.9 (m, vinylic), 4.5–5.1 (m, CH2), 4.13 (q, J = 7 Hz, Me); 13C NMR (CDCl3) δ 127.6, 112.1, 134.8, 113.2, 14.5, 61.7, 154.1.2, 5 Solubility: (1) readily sol dioxane and toluene; (2) sol dioxane. Preparative Methods: The synthesis of various N-acyl-1-amino-1,3-dienes have been described in detail.6-10 The following, which uses a Curtius rearrangement (eq 1),7 illustrates the procedure commonly used in the synthesis of (1) and (2). (1) Handling, Storage, and Precautions: in general, acyl azides are potentially explosive. Therefore solutions containing acyl azides should not be evaporated to dryness.5 Both (1) and (2) are stable solids, which can be stored in a freezer for several months. However, they are acid-sensitive and may be decomposed by traces of deuterium chloride present in chloroform-d.5 In rigorously degassed (oxygen-free) solutions, these diene carbamates are stable for extended periods even at 140 °C and this has been a critical factor in their successful reactivity with poor dienophiles.2