Chloride condensation nuclei

Alkyl Isoquinolines. Coal tar contains small amounts of l-methylisoquinoline [1721-93-3] 3-methylisoquinoline [1125-80-0] and 1,3-dimetliylisoquinoline [1721-94-4J. The 1- and 3-methyl groups are more reactive than others in the isoquinoline nucleus and readily oxidize with selenium dioxide to form the corresponding isoquinoline aldehydes (174). These compounds can also be obtained by the hydrolysis of the dihalomethyl group. The 1- and 3-methyhsoquinolines condense with benzaldehyde in the presence of zinc chloride or acetic anhydride to produce 1- and 3-styryhsoquinolines. Radicals formed by decarboxylation of carboxyUc acids react to produce 1-aIkyhsoquinolines. 

Here we see clearly the large concentration of density around the oxygen nucleus, and the very small concentration around each hydrogen nucleus. The outer contour is an arbitrary choice because the density of a hypothetical isolated molecule extends to infinity. However, it has been found that the O.OOlau contour corresponds rather well to the size of the molecule in the gas phase, as measured by its van der Waal s radius, and the corresponding isodensity surface in three dimensions usually encloses more than 98% of the total electron population of the molecule (Bader, 1990). Thus this outer contour shows the shape of the molecule in the chosen plane. In a condensed phase the effective size of a molecule is a little smaller. Contour maps of some period 2 and 3 chlorides are shown in Figure 8. We see that the electron densities of the atoms in the LiCl molecule are only very little distorted from the spherical shape of free ions consistent with the large ionic character of this molecule. In... 

A totally different picture is presented by 3-phenylazo-2-naphthol. This unusual isomer cannot be prepared by a normal coupling procedure but has been obtained by reaction of 3-amino-2-naphthol with thionyl chloride to give the N-sulphinylamine (4-24), condensation of which with N-phenylhydroxylamine yields the desired product [59]. Here, assumption of a ketohydrazone form would entail loss of aromatic character in both rings of the naphthalene nucleus and the energetic unfavourability of this situation ensures that the compound exists solely in the hydroxyazo form. 

Following resolution with (—)-quinine, (+)-465 was transformed into the (-l->2-formamido derivative which was condensed with the acid chloride of (+)-465 to give the secondary amide 468. From this point, the cyclic imidate salt 469 was prepared, but cyclization to the dodecahedrane nucleus could not be realired With Thiele s add as starting material, several routes to triquinacene and 2,3-dihydrotriquinacen-2-one 462) have been developed Triquinacene reacts with Mo(CO)g to give tricarbonyl(triquinacene)molybdenum (470) and with (CHjCI -... 

Much the same activity is retained when the nitrogen atoms in the heterocyclic nucleus are shifted around. The convergent scheme to this related compound starts with the acylation of alanine (35-1) with butyryl chloride (35-2). The thus-produced amide (35-3) is then again acylated, this time with the half-acid chloride from ethyl oxalate in the presence of DMAP and pyridine to afford the intermediate (35-4). In the second arm of the scheme, the benzonitrile (35-5) is reacted with the aluminate (35-6), itself prepared from trimethyl aluminum and ammonium chloride, to form the imidate (35-7). Treatment of this intermediate with hydrazine leads to the replacement of one of the imidate nitrogen atoms by the reagent by an addition-elimination sequence to form (35-8). Condensation of this product with (35-4) leads to the formation of the triazine (35-9). Phosphorus oxychloride then closes the second ring... 

Numerous condensation polymers such as polyamides (75MI11103) containing the pyridine nucleus in the backbone have been prepared from the corresponding pyridine diesters or diacid chlorides. The Knoevenagel condensation (Scheme 32) has provided another way of incorporating the pyridine nucleus into a condensation framework. Poly(styrylpyridines) (116) have been found to exhibit exceptional flame resistance and are useful in reinforced composites (79USP4163740). 

In this section, consideration will be given to the actual processes of acetal- or ketal-formation and not to the more indirect methods by which acetals and ketals of the polyhydric alcohols may be synthesized from compounds (e.g. derivatives of the monosaccharides) containing preformed alkylidene or arylidene groupings. The condensation of a carbonyl compound with a glycol is facilitated by acidic catalysts, and, since the reaction is reversible, by dehydration. The catalysts most frequently employed are concentrated sulfuric, hydrochloric and hydro-bromic acids, gaseous hydrogen chloride, zinc chloride and cupric sulfate others are phosphorus pentoxide, sulfosalicylic acid, and anhydrous sodium sulfate. The formation of benzylidene compounds is promoted less efficiently by phosphorus pentoxide than by either concentrated sulfuric acid or concentrated hydrochloric acid 1" the reaction is assisted by chloro- and nitro-substituents on the aromatic nucleus, but hindered by methyl- and methoxy-groups.18... 

Selenophene chloromethyl derivatives readily form di(/3-hydroxy-ethyl)aminomethylselenophenes (8) which, with thionyl chloride, give the corresponding di(/3-chloroethyl)aminomethylselenophenes (9).103 Chloromethylselenophenes condense with trisubstituted ethylene-diamines to yield tetrasubstituted diamines containing the selenophene nucleus.104 The reaction of 2-chloromethylselenophene with sodium derivatives of malonic and acetoacetic ester yields the acid (10) and ketone (11), respectively, whereas with alkyl magnesium halides 2-(alkylmethyl)selenophenes are formed.105... 

An efficient solvent-free synthesis of 1,2,4-oxadiazoles 235 was described using microwave irradiation by reaction of acyl chlorides with amidoximes <03H(60)2287>. The same kind of condensation was used for the synthesis of unnatural p and a-amino acids, 237 and 239 respectively, with an oxadiazole nucleus, using different derivatives of aspartic acid... 

Scott et al. [70TL4083 72JHC(P1)2224] reported the condensation of hydrazonyl chlorides of type 63 with 1,2-diaminoethane in aqueous diox-ane to produce 3-aryl-5,6,7-trihydroimidazolo[2,l-c] 1,2,4-triazoles (65). Fusion of an imidazole ring onto a triazole nucleus was the approach used (78UKZ725) in the reaction of 3-amino-2-methyl-5-substituted-l,2,4-triazole (66) with a-haloketones in the presence of perchloric acid to give l-methylimidazolo-[2,l-c]l,2,4-triazolium ions (67). 

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