Chloro benzaldehyde

Furthermore, in analogy to the aldol reaction, a-chloro-a,3-unsaturated esters have been observed—likely the result of 3-elimination of water from the intermediate halohydrin. For example, when benzaldehyde is condensed with the enolate of 17, chloride 19 was obtained. ... 

In 1972, van Leusen, Hoogenboom and Siderius introduced the utility of TosMIC for the synthesis of azoles (pyrroles, oxazoles, imidazoles, thiazoles, etc.) by delivering a C-N-C fragment to polarized double bonds. In addition to the synthesis of 5-phenyloxazole, they also described reaction of TosMIC with /7-nitro- and /7-chloro-benzaldehyde (3) to provide analogous oxazoles 4 in 91% and 57% yield, respectively. Reaction of TosMIC with acid chlorides, anhydrides, or esters leads to oxazoles in which the tosyl group is retained. For example, reaction of acetic anhydride and TosMIC furnish oxazole 5 in 73% yield. ... 

Ring closure of 2-chloro-l-phenethylpyridinium ion (247) (prepared in situ) to l,2-dihydro-3,4-benzoquinolizium ion involves intramolecular nucleophilic displacement of the chloro group by the phenyl 77-electrons. A related intermolecular reaction involving a more activated pyridine ring and more nucleophilic 7r-electrons is the formation of 4-( -dimethylaminophenyl)pyridine (and benzaldehyde) from dimethylaniline and 1-benzoylpyridinium chloride (cf. Section III,B,4,c). 

A -Chloromethylamine attacks ketones in alkaline solution with formation of oxaziranes with cyclohexanone, compound 17 is produced in 50% yield. The reaction with aldehydes with zV-chloromethyl-amine yields predominantly acid amides. However, oxaziranes are also produced here as by-products. From benzaldehyde and A -chloro-methylamine, 2-raethyl-3-phenyloxazirane (15) was obtained in 10% yield. 

Sterically hindered derivatives of isoxazole carboxylic acids have yielded a goodly number of antibiotics. Chlorination of the oxime of the appropriately substituted benzaldehydes (15) leads to the intermediates, ( 16. Condensation of the chloro oximes with ethyl acetoacetate in base gives the esters (17) of the desired isoxazole carboxylic acids. Alternately, the esters... 

The anion produced by VNS of nitroarenes andct-chloro esters is hydroxylated by the ac of air and benzaldehyde, thereby producing ct-hydroxy esters fEq 9 37,... 

Triphenylphosphine, in preparation of dichloromethylenetriphenyl-phosphorane, 46, 33 reaction with N,N-dimethylamino-benzaldehyde to yield /9,0-di-chloro-p-dimethylaminostyrene, 46,33... 

Chiral (2 )-(Z)-l-methyl-2-butenylboronate 13 was synthesized by way of a-chloroethylboronate 12,0. This route, in which the dichloromethyl starting material is first alkylated with methyllithi-um and then 12 is treated with (Z)-2-propenyllithium, was developed since a-chloro-2-butenyl-boronates such as 7 and 15 are sensitive to racemization, owing to the presence of nucleophilic chloride ions, during the reactions of (4f ,5/ )-2-(dichloromethyl)-4,5-dimethyl-l,3,2-dioxa-borolane and (Z)- or ( )-2-propenyllithium. The route to 13 may be performed as a one-pol operation with an overall yield of >90%. The diastereomeric purity of 13 was estimated to be >98% based on a subsequent reaction with benzaldehyde. 

Reaction of pyridines with dialkyl acetylenedicarboxylates in the presence of isocyanates in dry CH2C12 at room temperature produced 1-substituted 2-oxo-l,9a-dihydro-2/7-pyrido[l,2-tf]pyrimidine-3,4-dicarboxylates <2004TL1803>. One-pot, three-component synthesis of 1-substituted 2-oxo-l,llb-dihydro-2//-pyrimido[2,l- ]iso-quinoline-3,4-dicarboxylates and 4-(3-chloro-4-methylphenyl)-3-oxo-4,4a-dihydro-3/7-pyrimido[l,2-tf]quinoline-l,2-dicarboxylate was realized by the reaction of isoquinoline and quinoline with isocyanates and dialkyl acetylenedicarboxylates <2004S861>. Diastereomeric mixtures of l-tosyl-2-aryl-l,llb-dihydro-2/7-pyrimido[2,Ttf]isoquinoline-3,4-dicarboxylates were obtained from isoquinoline, iV-tosyl-benzaldehyde imines, and DMAD <2002OL3575>. 

Other electrophilic substitution reactions on aromatic and heteroaromatic systems are summarized in Scheme 6.143. Friedel-Crafts alkylation of N,N-dimethyl-aniline with squaric acid dichloride was accomplished by heating the two components in dichloromethane at 120 °C in the absence of a Lewis acid catalyst to provide a 23% yield of the 2-aryl-l-chlorocydobut-l-ene-3,4-dione product (Scheme 6.143 a) [281]. Hydrolysis of the monochloride provided a 2-aryl-l-hydroxycyclobut-l-ene-3,4-dione, an inhibitor of protein tyrosine phosphatases [281], Formylation of 4-chloro-3-nitrophenol with hexamethylenetetramine and trifluoroacetic acid (TFA) at 115 °C for 5 h furnished the corresponding benzaldehyde in 43% yield, which was further manipulated into a benzofuran derivative (Scheme 6.143b) [282]. 4-Chloro-5-bromo-pyrazolopyrimidine is an important intermediate in the synthesis of pyrazolopyrimi-dine derivatives showing activity against multiple kinase subfamilies (see also Scheme 6.20) and can be rapidly prepared from 4-chloropyrazolopyrimidine and N-bromosuccinimide (NBS) by microwave irradiation in acetonitrile (Scheme... 

These reaction conditions also permit the chemoselective quantitative reduction of benzaldehyde to benzyl alcohol without any concomitant reduction of either acetophenone or 3,3-dimethylbutan-2-one present in the same reaction mixture.83 Additionally, this useful method permits the reduction of aldehyde functions in polyfunctional compounds without affecting amide, anhydride, eth-ylenic, bromo, chloro, or nitro groups.79,80,319... 

Azidobenzaldehyde, 2697 f Benzaldehyde, 2731 f Butyraldehyde, 1607 Chloroacetaldehyde oxime, 0787 2-Chloro-6-nitrobenzaldehyde, 2650... 

A classic paper by Baizer and Chruma [35] describes synthetic applications based on the reduction of allyl halides. Electrolyses of 4-bromo- and 4-chloro-2-butene can be employed for the allylation of acetone and benzaldehyde [36], and the reduction of allyl halides in the presence of trimethylchlorosilane affords silylated compounds [34]. 

Similarly, the authors also examined the stabilization effect of dynamic modification of a U-NH -appended RNA aptamer that forms a kissing complex with the HIVl transactivation-responsive RNA element TAR. In this dynamic library, 2-chloro-6-methoxy-3-quinofinecarboxaldehyde (Rd) was incorporated in place of benzaldehyde (Ra). After equilibration of the U-NHj-substituted aptamer and aldehydes Rb-Rd in the presence of the TAR RNA target, it was found that the nalidixic aldehyde Rc-appended RNA was amplified 20%, and accompanied by an increased (Fig. 3.17). Interestingly, the nalidixic aldehyde Rc was selected in both DNA and RNA complexation experiments. 

The sediment concentrations of anthropogenic compounds in the cove were somewhat less variable than upstream this probably reflects the greater bottom uniformity of the cove. Fewer of the plant s compounds were detected in sediment from the channel where the cove leads into the brackish river (Point 18, Figure 1). Found at this location were various phenols (no. 28, 30a, 30b, 31, 33, 38, 39), di-t-butyl-benzoqui-none (no. 57), 3,5-di-t-butyl-4-hydroxy-benzaldehyde (no. 35), three benzotriazoles (no. 6, 10, 12), 4,4 -dichloro-3(trifluoromethyl) carbanilide (no. 77), and 2-chloro-4,6-bis-isopropylamino-s-triazine (no. 14). The only compounds from the plant detected in the sediment sample from the brackish river (Point 19) were the two high molecular weight benzotriazoles (no. 10 and 12) and methyl 3-(3 ,5 -di-t-butyl-4 -hydroxphenyl) propionate (no. 46). 

The cross-coupling reaction of homoallylic alcohols with aldehydes in the presence of bismuth trichloride in solvent-free conditions under microwave irradiation generated 4-chloro-2,6-disubstituted tetrahydropyrans with high c/.v-diastereos-electivity [15]. The reaction of benzaldehyde with l-phenyl-3-buten-l-ol in the presence of bismuth trichloride under microwave irradiation gave the corresponding... 

Starting from the findings of the racemic cross-benzoin condensation [66], and assuming that aldehydes not accepted as donor substrates might still be suitable acceptor substrates, and vice versa, a mixed enzyme-substrate screening was performed in order to identify a biocatalytic system for the asymmetric cross-carboligation of aromatic aldehydes. For this purpose the reactions of 2-chloro-(40a), 2-methoxy- (40b) and 2-methylbenzaldehyde (40c), respectively, were studied with different enzymes in combination with benzaldehyde (Scheme 2.2.7.23) [67]. The three ortho-substituted benzaldehyde derivatives 40a-40c were... 

Using only benzaldehyde as substrate (see Fig. 3.1.8a), (R)-benzoin can be obtained on a 200 mg scale from a 40 mb two-phase system. This corresponds to a volumetric productivity of 53 g L d for the organic phase, or 20 g d with respect to the overall reaction volume. When using 2-chlorobenzaldehyde and 3-methoxybenzaldehyde as substrate in equimolar amounts, (R)-2-chloro-3 -methoxybenzoin is formed as the main product with approximately 80% selectivity (see Fig. 3.1.8b). The symmetric benzoins (2,2 -dichlorobenzoin, 3,3 -dimethoxybenzoin) are formed as side-products. The main product is obtained on a 150 mg scale, which corresponds to a volumetric productivity of 40 g L d with regard to the organic phase. 

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