Synthesis of ring-alkylated isoproterenol derivatives

Abstract

2-Propyl-, 5-propyl-, and 6-propylisoproterenols (2a, 2b, and Id, respectively) have been synthesized as models for polymer drug conjugates. Key intermediates were the propenylbenzaldehydes 3a-c. The (isopropylamino)phenethanol side chain was constructed from the aldehyde functionality by the method of Avery et al.2 The benzaldehyde 3b was prepared from 3,4-dihydroxybenzaldehyde (7) by selective alkylation at the 4-hydroxyl followed by Claisen rearrangement and benzylation of the phenolic hydroxyls. Selective alkylation at the 3-hydroxyl Approach to the Total Synthesis of Chlorothricolide: Synthesis of "7-epi-Bottom Half' and Its Union with "Top Half' Systems

Cyclophane-Type Fullerene-dibenzo[18]crown-6 Conjugates withtrans-1,trans-2, andtrans-3 Addition Patterns: Regioselective Templated Synthesis, X-Ray Crystal Structure, Ionophoric Properties, and Cation-Complexation-Dependent Redox Behavior

“…IR (KBr): 3374m (br. ), 2922w, 2877w, 1593w, 1518s, 1430m, 1328w, 1260s, 1168m, 1137s, 1062w, 961w, (6,7,9,10,17,18,20,k] [1,4,10,13,16]hexaoxacyclooctadecin-2,14-diyl)dimethylene] Bis(malonate) (10) and 4. Et 3 N (0.3 ml, 2.10 mmol) was added via syringe over 5 min at 08 to 7/9 1 : 1 (0.4 g, 0.95 mmol), then EtO 2 CCH 2 COCl (0.28 g, 2.10 mmol) in DMF (15 ml, dried over 4-molecular sieves) was added in the same way.…”

“…In the synthesis of 4 (Scheme 1), 3,4-dihydroxybenzaldehyde was regioselectively alkylated with an excess of bis(2-chloroethyl) ether to give 5 as colorless needles [17]. The two minor side-products, the regioisomer of 5 formed by alkylation of the OH group at C(3) (a yellow oil) and the compound resulting from linking two 3,4-dihydroxybenzaldehyde molecules, could be readily separated.…”

Synthesis of Deuterium-Labeled Cryptophane-A and Investigation of Xe@Cryptophane Complexation Dynamics by 1D-EXSY NMR Experiments

“…Prior to the Fourier transform an exponential apodization (lb 20.0) was applied. (8): [19] Allyl bromide (30.24 g, 0.25 mol) was added in one portion to a stirred solution of 3,4-dihydroxybenzaldehyde (7,13.81 g, 0.1 mol), lithium carbonate (18.47 g, 0.25 mol), and freshly distilled DMF (250 mL). The mixture was then stirred overnight at 55 8C under argon.…”

Regioselektive, durch einen Kronenether- Spacer kontrollierte Synthese vontrans-1- Fulleren-Bisaddukten: Alkalimetallionen- abhängige Redoxeigenschaften von Fulleren-Kronenether-Konjugaten

“…Die Umkristallisation aus CH 2 Cl 2 /n-Hexan gab farblose Kristalle von [Re 5 (m-H) 5 (CO) 20 ]. IR (thf): n Ä(CO) 2107m, 2094w, 2038vs, 2013s, 1968mw cm À1 ; 1 H-NMR ([D] 8 Stichwörter: Carbonylkomplexe´Cluster´Hydride´Iso-lobalbeziehungen´Rhenium o (SHELX97), [12] [11] und anschlieûende Fourier-Synthesen, anisotrope Volle-Matrix-kleinste-Fehlerquadrate-Verfeinerung gegen F 2 o (SHELX97), [12] erwies sich die Entwicklung von ausgedehnteren, konformativ starren Spacern, die die Kohlenstoffkugel vollständig umspannen und somit den zweiten Addenden in die trans-2und vor allem die trans-1-Stellung lenken, als besonders schwierig. [6] Unter den bis zu acht regioisomeren C 60 -Bisaddukten, die in unterschiedlichen doppelten Additionen ohne Spacer gebildet werden, [7,8] fallen die trans-1-Derivate aus kinetischen und statistischen Gründen zumeist in sehr geringer Ausbeute an.…”

“…[12] Die durch einen Templateffekt der K -Ionen [13] unterstützte Makrocyclisie- rung von 5 lieferte den Dialdehyd 6, der zum Diol 7 reduziert und anschlieûend in das Bismalonat 4 überführt wurde. [14] Die doppelte, modifizierte Bingel-Reaktion [2 a, b] von 4 mit C 60 lieferte schlieûlich das trans-1-Bisaddukt (AE)-1 (30 %) neben einer geringen Menge des trans-2-Derivates (AE)-2 (2 %).…”