Dichloro benzaldehyde

In recent years there has been a growing interest in the use of polymeric herbicides, pesticides and drugs. Several reviews have appeared on this general area (69-71) and we earlier noted several examples of such potential behavior with poly(vinyl alcohol) modifications. These included modifications containing 6-methylthiopurine (an antileukemia drug) (55), 2,6-dichloro-benzaldehyde (a herbicide) (56), various enzymes (52,53), aspirin (analgesic)(51) and mercapto groups (46-49). 

Benzaldehyde diclobutrazol, difenzoquat, diniconazole, diphenamid, warfarin, see chlorobenzaldehyde, dichloro benzaldehyde Benzamidine fenclorim Benzazimide azinphosmethyl... 

In water approx. 1 g/litre soluble in alcohols, ketones, ether Oxidisable to 2,4-dichloro benzaldehyde... 

Obtained by reaction of 3,4-dichloro-benzaldehyde with 4-propionylpyrogallol in the presence of hydrochloric acid in refluxing ethanol for 30 min [6454]. 

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). 

Tetraphenylporphin (H2TPP) was prepared from pyrrole and benzaldehyde (25). The tetraphenylchlorin contamination was oxidized by use of 2,3-dichloro-5,6-dicyano-p-benzoquinone (26). Octaethylporphin (H2-OEP)was prepared by the method of Paine et al.(27) from 3,4-diethyl-2-ethoxy-carbony1-5-methyl-pyrrole (28). Zinc(II)-tetraphenylporphin (ZnTPP) was prepared by refluxing H2TPP and zinc acetate in dimethyl-formamide (29). ZnTPP was dissolved at a concentration of 10 -10 ... 

This method of preparation of a halobenzaldehyde is of wide application and has been used for the preparation of the following substituted benzaldehydes 2-bromo-5-methyl-,4 2,3-dichloro-and 2,4-dichloro-,5 2-chloro-4-methyl-,-iodo-, />-fluoro-, 2-iodo-4-methyl-, and 6-iodo-3-methyl-.9... 

Under mild conditions, isosorbide (3) is converted into 1,6-dichloro-1,6-dideoxy-D-glucitol (147) by reaction with boron trichloride (Scheme 41). Compound 147, which was not isolated in pure form, was allowed to react with benzaldehyde to afford 2,4-(3-benzylidene-1,6-dichloro-1,6-dideoxy-D-glucitol (148) and 2,4 3,5-di-O-benzylidene-1,6-dichloro-1,6-dideoxy-D-glucitol (149). By this method, the two tetrahydrofuran rings are cleaved in a very mild manner.218... 

Highly porous silica gel served as a support for the TADDOL moiety derived from inexpensive and readily available i-tartaric acid, which provided access to htanium-based Lewis acid catalysts (Heckel, 2000). Such entihes are employed successfully for enantioselective reactions. TADDOLs were covalently attached to the trimethyl-silyl-hydrophobized silica gel, controlled-pore glass (CPG) at about 300 m2 g-1, at a loading of 0.3-0.4 mmol gl (Heckel, 2002). In a carefully monitored mulh-step immobilization procedure, the TADDOLs were titanated to yield dichloro-, diisopropyl-, or ditosyl-TADDOLates. These catalysts were employed in dialkylzinc addihon to benzaldehydes and diphenyl nitrone addihon to 3-crotonyloxazolidinone, a [3+2] cycloaddition. 

Tri- and Tetra-Substituted Benzaldehydes. No important deviation from the limitations discussed above are to be noted when further substituents are present, provided that at least one position ortho to the formyl group is open. When an ortho or para hydroxyl group is present neither dismutation nor cleavage occurs under the usual conditions of the reaction. An ortho-amino group acts similarly 2,5-dichloro-6-aminobenzaldehyde was recovered after treatment with 50% KOH at 100° for four hours.78 0... 

The 1-hydroxyl group of XXV has a sufficiently strong attachment to the carbon atom to prevent the ready prior transformation to the open form before the hydrogenation.1 This anhydride acetate XXXII is a thick distillable oil that no longer exhibits an aldehyde reaction. After deacetylation, a crystalline benzylidene derivative1 can be prepared by treatment with benzaldehyde and zinc chloride. The action of phosphorus pentachloride on a thionyl ester of the deacetylated substance leads to an oily 4,6-dichloro derivative (XXXIII).1 ... 

Erythro- and Threo-2-( 1 -Hydroxybenzyl)cyclohexanones. A dichloro-methane (10 ml) solution of 1-trimethylsilyloxycyclohexene (0.426 g, 2.5 mmol) is added dropwise into a mixture of benzaldehyde (0.292 g, 2.75 mmol) and titanium(iv) chloride (0.55 g, 2.75 mmol) (2) in dry dichloro-methane (20 ml) under an argon atmosphere at — 78 °C, and the reaction mixture is stirred for 1 hour. After hydrolysis (with water) at that temperature, the resulting organic layer is extracted with ether, and the extract is washed with water and dried over anhydrous sodium sulphate. The extract is evaporated under reduced pressure, and the residue is purified by column chromatography (silica gel). Elution with dichoromethane affords 115 mg (23%) of eryt/jro-2-(r-hydroxybenzyl)cyclohexanone, m.p. 103 °C (recrystallised from propan-2-ol, m.p. 103.5-104.5 °C) i.r. 3530 (OH), 1700 (C=0)... 

Similar reaction with benzaldehyde or pivalaldehyde led to 6-phenyl- and 6-/-butyl-dibenzo[//,g][l,3,6]trithiocins 133 in good yields (Scheme 34 <1998BCJ1187>). Reaction of bis(o-mercapto)phenyl sulfide with 1,2-rxr-dichloro-ethylene produced 6-methylenedibenzo[//,g][l,3,6]trithiocine 11 as a mixture with 18-membered product 134 instead of an expected nine-membered dibenzo[3/][l,4,7]trithionine <1999T10057>. 

Chirala-phenylalkanamines. The hydrazine [(R)-(-)-4] was transformed into the hydrazone [(R)-(-)-5] upon reaction with benzaldehyde in the presence of anhydrous MgS04 in dichloro-... 

The tedious preparation of the monopyrrolic precursor 2.147 necessary for the tris-(phenyl)cobalt(III) corrole 2.153 led Paolesse, et al. to consider a third approach to preparing tris-(phenyl)cobalt(III) corroles. It centers around an initial acid-catalyzed condensation between the diacid dipyrrylmethane 2.144 with benzaldehyde (2.154) that is followed by a subsequent cyclization step carried out in the presence of Co(OAc)2 and PPh3. In this case, it was found that 2,3-dichloro-5,6-dicyano-I,4-benzoquinone (DDQ) helped mediate the requisite final oxidation step. While this approach did give a slightly lower yield of corrole (18%), it had the advantage of being quite streamlined. 

The rate of allylation of aldehydes with allyltrichlorosilane is greatly influenced by 0-donor ligands [51]. The reaction of benzaldehyde with allyltrichlorosilane was promoted by a stoichiometric quantity of DMF in combination with various salts. When the salts are added to the reaction, a dramatic increase in the rate of allylation was observed. This effect is interpreted in terms of an ionization event at a key step in the reaction pathway. The dissociation of a chloride ion is proposed to create a reactive complex in solution. Conductivity experiments indicate that ion-paired complexes may play a role in the ligand-activated allyl- and 2-bu-tenylation of aldehydes. The conductivity of allyltrichlorosilane in dichloro-methane (a solvent which does not promote allylation) is 1000 times less than at the same concentration of allyltrichlorosilane in DMF. 

Full details for the preparation of dichloro ansa-bis-Ind and /msv2-bis(tetrahydroindenyl) titanium derivatives with the 2,5-diisopropylcyclohexane bridging group (Scheme 662) have been reported along with their X-ray structures. The compounds were used to catalyze the enantioselective pinacol coupling of benzaldehyde.1682... 

Similarly, the a-monochlorinated and a-monobrominated dimethyl 2-oxoalkylphosphonates are prepared in satisfactory yields (50%) by reaction of the sodium enolate of dimethyl 2-oxoalkyl-phosphonates with NCS or NBS in DME at room temperature- "- - or with bromine in Et20 (53-71%) or THE (60%) Synthesis of diethyl l-chloro-2-oxopropylphosphonate has also been reported through reduction of the 1,1-dichloro derivatives with sodium sulfite.- lodination in the Y-position of P-ketophosphonate 1,3-dianions prepared with KiCO, in MeOH has been reported. These dianions react with benzaldehyde in a Homer-Wadsworth-Emmons-Darzens reaction sequence to produce the a,P-unsaturated a, P -epoxyketones in 60-79% yields (Scheme 7.101).s ... 

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