By condensation with

Aldrin is obtained from the Diels-Alder addition product of cyclopentadiene and vinyl chloride by dehydrochlorination followed by condensation with hexachlorocyclopenta-diene. 

Its chief importance is as a source of cinnamic acid by condensation with sodium ethan-oate and ethanoic anhydride and as a source of triphenylmethane dyestuffs by condensation with pyrogallol, dimethylaniline, etc. It is also used in the manufacture of perfumes. 

It is used for the preparation of azines and oxazines by condensation with w-diamines and phenols. 

Primary sulphonamides RSOjNHj may be most simply characterised by condensation with xanthhydrol to yield the corresponding iV-xanthyl-sulphonamides ... 

A two-step synthesis of indoles from o-nitrobenzaldehydes proceeds by condensation with nitromcthanc followed by reductive cyclization. Like the Leim-gruber Batcho method, the principal application of the reaction is to indoles with only carbocyclic substituents. The forniation of the o,p-dinitrostyrenes is usually done under classical Henry condensation conditions but KF/18-crown-6 in propanol was found to be an advantageous reaction medium for acetoxy-substituted compounds[1]. The o,p-dinitrostyrenes can also be obtained by nitration of p-nitrostyrenes[2]. 

C From indole-3-carboxaldehvdes by condensation with nitroalkanes ... 

In a similar way the use of the 2-methyl-3-isothiocyanato-4-thiocyanato-hept-3-ene (252) prepared from thiocyanogen and the oxoal-kylene phosphorane (251) yields the 2-anilino-4-propyl-5-isopropyl-thiazole (253) by condensation with aniline (Scheme 128). 

Bisa.codyl, 4,4 -(2-PyridyLmethylene)bisphenol diacetate [603-50-9] (Dulcolax) (9) is a white to off-white crystalline powder ia which particles of 50 p.m dia predominate. It is very soluble ia water, freely soluble ia chloroform and alcohol, soluble ia methanol and ben2ene, and slightly soluble ia diethyl ether. Bisacodyl may be prepared from 2-pyridine-carboxaldehyde by condensation with phenol and the aid of a dehydrant such as sulfuric acid. The resulting 4,4 -(pyridyLmethylene)diphenol is esterified by treatment with acetic anhydride and anhydrous sodium acetate. Crystallisation is from ethanol. 

Nifuratel. Nihiratel, 5-[(methylthio)methyl]-3-[5-nitro-2-furanyl)-methyleneamino]-2-oxazohdinone, is prepared by treatment of the appropriate methyl-thiohydrazinopropanol with diethylcarbonated followed by condensation with 5-nitro-2-furancarboxaldehyde diacetate (44). The product has been used in antibacterial, antifungal, and antiprotozoal appHcations. 

The dye has been degraded by a fusion with caustic potash and the degradation products identified as various o-anilinyl mercaptans. They were identified and characterized by condensation with monochloroacetic acid to give the thioglycohc acids which, on acidification, were converted to well-defined crystalline lactams (2—4) together with a small amount of ji)-aminobenzoic acid. 

Methylenetetrahydrofohc acid (5,10-CH2-H4 folate) (5) is a coen2yme in thymidylate biosynthesis the natural (6R)-stereoisomer is prepared by en2ymatic reduction of H2 folate (2), foUowed by condensation with formaldehyde (54). 

Two of the remaining colorants on the Hst of certifiables are quinoliaes the solvent-soluble D C Yellow No. 11 (30b), and its water-soluble sulfonated derivative, D C Yellow No. 10 (30a) (Fig. 2). Both are derived from quiaaldine by condensation with phthaUc anhydride. 

Monooximes of a-diketones have found applicability in the synthesis of 2-aminopyrazine 1-oxides by condensation with a-aminonitriles, and this reaction was used by White and coworkers in an approach to the synthesis of Cypridina etioluciferamine (Scheme 66 R = 3-indoloyl) (73T3761). In this instance, the use of TiCU as a catalyst was essential, since the carbonyl group in 3-acylindoles is normally deactivated and the required amine/carbonyl condensation is impractically slow. Under normal circumstances the carbonyl group in simple alkyl-substituted monoximes of a-diketones is the more reactive site and the reaction is rapid, requiring no catalysis (69LA(726)loo). 

Melamine (I,3,5-triamino-2,4,6-triazine) was first prepared by Liebig in 1835. For a hundred years the material remained no more than a laboratory curiosity until Henkel patented the production of resins by condensation with formaldehyde. Today large quantities of melamine-formaldehyde resins are used in the manufacture of moulding compositions, laminates, adhesives, surface coatings and other applications. Although in many respects superior in properties to the urea-based resins they are also significantly more expensive. 

Anhalonine and Lophophorine. Spath and Gangl showed that each of these alkaloids contains a methylenedioxy group and that the quarternary iodide prepared from dZ-anhalonine is identical with lophophorine methiodide so that lophophorine must be N-methylanhalonine. Anhalonine was synthesised from 3 4-methylenedioxy-5-methoxybenzaldehyde by condensation with nitromethane, reduction of the product to the corresponding -ethylamine, the acetyl derivative (VII) of which, on treatment with phosphoric anhydride, condensed to 6-methoxy-7 8-methylenedioxy-l-methyl-3 4-dihydrofsoquinoline, m.p. 60-2°. This, on reduction, furnished the corresponding tetrahydrofsoquinoline, which proved to be anhalonine (VIII), and on conversion to the quaternary methiodide the latter was found to be lophophorine (IX) methiodide. The possible alternative, 8-methoxy-6 7-methylenedioxy-l 2-dimethyl-l 2 3 4-tetrahydrofsoquinoline, was prepared by Freund s method and the methiodide shown not to be identical with lophophorine methiodide. 

Dihydro- -strychnine, C21H24O3N2, m.p. 240-3° (vac.), [a]D38-7/d (CHCI3), forms a methyl ether, m.p. 209° (vac.) and a benzylidene derivative, m.p. 209-215° (Leuehs and Rack, 1940). Unlike -strychnine, the dihydro-derivative can be converted, either by boiling with acetic anhydride or by condensation with malonie acid, into the corresponding 9-acetie acid, in this ease dihydrostrychnine-9-acetie acid, C23H26O4N2, m.p. 300-3° (vac. dec.), 43-0° (H2O) (Leuehs et al., 1942). 

The Pictet-Spengler reaction is an acid-catalyzed intramolecular cyclization of an intermediate imine of 2-arylethylamine, formed by condensation with a carbonyl compound, to give 1,2,3,4-tetrahydroisoquinoline derivatives. This condensation reaction has been studied under acid-catalyzed and superacid-catalyzed conditions, and a linear correlation had been found between the rate of the reaction and the acidity of the reaction medium. Substrates with electron-donating substituents on the aromatic ring cyclize faster than the corresponding unsubstituted compounds, supporting the idea that the cyclization process is involved in the rate-determining step of the reaction. 

The alkaloid rutaecarpine (111) was synthesized from l-oxo-1,2,3,4-tetrahydro-)3-carboline (183 R = H) by condensation with methyl anthranilate in the presence of phosphorous chloride or by heating... 

Bromo-7-methyl-6-methylaminoquinoline was nitrated with ACONO2 to give the 6-N(N02)Me derivative, which rearranged in diluted sulfuric acid to the 5-nitro derivative. Reduction of the latter compound, followed by condensation with BrCN and final hydrogenolysis using H2, led to a product of >99% radiochemical purity (85MI1). 

The preparation of the selenazolyl-pyrazolones was then effected by a second method, in which first the pyrazolone ring and afterward the selenazole ring was formed. For this purpose -ketoester seleno-semicarbazones were first converted to the corresponding 1-seleno-carbamoyl-3-aIkylpyrazol-5-one. These, by condensation with a-halo-genocarbonyl compounds according to the Hantzsch synthesis, formed the selenazole ring as a second step (17). 

Replacement of the methyl ketone moiety in 78 by a phenyl sulfoxide, interestingly, leads to a relatively potent uricosuric agent with diminished antiinflammatory action. This effect in lowering serum levels or uric acid leads to the use of this drug in the treatment of gout. Alkylation of diethyl malonate with the chlorosulfide, 79, gives the intermediate, 80. The pyrazolodione (81) is prepared in the usual way by condensation with hydrazobenzene. Careful oxidation of the sulfide with one equiv-... 

Azelastine (107) is an antiallergic/antiasthmatic agent prepared from 4-chlorobenzyl-2 -car-boxyphenylketCHie (105) by condensation with hydrazine to give the phthalazinone (106) followed by reaction of the sodium salt of this last with 2-(2-chloroethyl)-N-methylpyrrolidine (presumably involving nucleophilic ring expansion of the bicyclic quaternary salt putatively formed as a first product) to complete the synthesis [30]. 

Acylation of the common starting 3,4-diaminonitrobenzene with furoyl chloride proceeds on the more basic amino group meta to the nitro group to give 140. This is then cyclized to imidazole 141 by means of acetic anhydride. Reduction of the nitro group (142), followed by condensation with ethyl acetoacetate affords furodazole (143) [26]. 

C. 2-Carbethoxycyclohexanone by Condensation with Ethyl Diethoxyphos-PHiNYL Formate... 

The 2-phenyl-2-ethyl-pentane-1,5-diacid-mononitrile-(1) of melting point 72° to 76°C, used as starting material in this process, can be produced for example from o-phenyl-butyric acid nitrile by condensation with acrylic acid methyl ester and subsequent hydrolysis of the thus-obtained 2-phenyl-2-ethyl-pentane-1,5-diacid-monomethyl ester-mononltrile-(l) of boiling point 176° to 185°C under 12 mm pressure. 

Polyacrylamide may be converted into a sulfo-methyl derivative by condensation with formaldehyde and sodium bisulfite under basic conditions. 

Fatty acids, both saturated and unsaturated, have found a variety of applications. Brassilic acid (1,11-un-decanedicarboxylic acid [BA]), an important monomer used in many polymer applications, is prepared from erucic acid (Scheme 2), obtained from rapeseed and crambe abyssinica oils by ozonolysis and oxidative cleavage [127]. For example, an oligomer of BA with 1,3-butane diol-lauric acid system is an effective plasticizer for polyvinylchloride. Polyester-based polyurethane elastomers are prepared from BA by condensing with ethylene glycol-propylene glycol. Polyamides based on BA are known to impart moisture resistance. 

Originally, 1,19-unsubstituted or 1,19-dicarboxylated biladienes-ac were prepared75 for the synthesis of corroles (See Section 1.6.), but by condensation with formaldehyde they give the corresponding porphyrins, e.g. 14. The method is especially valuable for the introduction of isotopic labels from the formaldehyde moiety.76... 

This ring system may be prepared from 527 by condensation with ami-drazone or aminoguanidine derivatives to afford 528, which on reaction with polyphosphoric acid gave imidaz[5, -/][ ,2,4]triazin-4(2//)one 529... 

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