1.3- Bis benzaldehyde

Phenyl Bis[benzaldehyde thiosemicarbazone] Tellurium Chloride A solution of 1.0 g (3.2 mmol) phenyl tellurium trichloride in 30 w/ methanol is added to a solution of 2.3 g (12.8 mmol) benzaldehyde thiosemicarbazone in 30 ml of warm water. The mixture is stirred for 0.5 h and then set aside for 12 h. The yellow crystals of the product arc filtered and recrystallized from methanol yield 79% m.p. 70-72°. 

A series of dibenzooxaaza macroeyeles have been prepared by a nontemplate cyclization of 1,5-diamino-3-pentanol and various bis-benzaldehyde compounds. The resulting cyclic bis Schiff base was reduced with sodium borohydride to give the dibenzodiaza-crowns in overall yields of 10-20%... 

Cyclization takes place when tert-butylisocyanide, benzaldehyde, anilinium chloride, and carbonyl(dicyano)cyclopentadienyl ferrate are reacted, the carbene complex 42 being the result (95JOM(491)135). /50-butyraldehyde, tert-butyl isocyanide, ammonium hexafluorophosphate, and [(T -Cp)Fe(CO)(CN)2] give the cationic bis-carbene 43. 

A chiral vanadium complex, bis(3-(heptafluorobutyryl)camphorato)oxovana-dium(IV), can catalyze the cycloaddition reaction of, mainly, benzaldehyde with dienes of the Danishefsky type with moderate to good enantioselectivity [21]. A thorough investigation was performed with benzaldehyde and different activated dienes, and reactions involving double stereo differentiation using a chiral aldehyde. 

Ooct-OPV3-CN was synthesized front (4-cyanomcthyI-2,5-bis( -oclyIoxy)phcn-yI)acetonitrile and benzaldehyde. Ooct-OPV5-CN was synthesized as depicted in Figure 16-8 front (4-cyanomethyI-2,5-bis(/i-octyIoxy)phenyl)acetonitrile and4-styr-ylbcnzaldehyde. 

Addition of anhydrous magnesium bromide to [l,3-bis(trimethylsilyl)-2-propenyl]lithium improves the antijsyn selectivity of the reaction with benzaldehyde from 80 20 to 94 6 23. 

Mit Lithiumalanat in siedendem Ather ist die Reduktion in 15, mit Natriumboranat/Aluminiumehlorid in Bis-[2-methoxy-athyl]-ather bei 75° in 30 Min. bcendet. Bei der Reduktion von Thiobenzoesaure mit einem Li-thiumalanat-UnterschuB wird auch Benzaldehyd erhalten4. 

Je nach Bedingungen kann auch Hexaathyl-disiloxan entstehen. Die bei 20° ablaufende Reaktion ist stark strukturabhangig. Elektronenliefernde Substituenten fordern, elektro-nenanziehende erschweren die Reduktion. So wird 4-Nitro-benzophenon z.B. erst inner-halb 47 Stdn. zu 4-Nitro-diphenylmethan reduziert, wahrend 4-Nitro-benzaldehyd und -acetophenon nicht bis zu Kohlenwasserstoffen reduziert werden. 

Mit Natrium-bis-[2-methoxy-athoxy]-dihydrido-aluminat konnen in sieden-dem Xylol Hydroxy-benzaldehyde und -acetophenone innerhalb weniger Stunden zu Al-kyl-phenolen reduziert werden (Vorschrift S. 171) z.B.2 ... 

Auf gleiche Weise liefert Benzaldehyd trans-Stilben (85% d.Th.) und Cycloheptanon Bi-cycloheptyliden (95% d.Th.). ji-Carotin ist mit 85% aus Retinal zuganglich. 

Benzaldehyd-diathylacetal2 Zu einer gekiihlten Losung von 7.6 g (0,034 Mol) Orthobenzoesaure-triathyl-ester in 10 m/ abs. Benzol wird unter Riihren und unter Stickstoff eine Losung von 4,8 g (0,034 Mol) Bis-[2-me-thyl-propyl]-aluminiumhydrid in 10 m/Benzol getropft, wobei die Temp, nicht liber 30°steigen darf. Man riihrt 1 Stde. bei 30° und fraktioniert Ausbeute 5,8 g (95% d.Th.) Kp13 140-142°. 

In groBerem MaBstab wird die reduktive Dimerisierung von 4-Hydroxy-benzaldehyd zu l,2-Bis- 4-hydroxy-phenyl]-glykol an Quecksilber durchgefiihrt6. 

AcetaUzation of benzaldehyde with trimethyl orthoformate can be carried out with a series of MOFs constructed from In and BDC or BTC ligands with open In sites. The catalysts are even stable in aqueous medium and can be reused without loss of activity. Owing to the small pores of these MOFs, the reaction only takes place at the outer surface of the crystals [54]. In another MOF constructed from In and 4,4 -(hexafluoroisopropylidene)bis(benzoic acid), the same reaction takes place inside the pores [55]. 

Fluoride-catalyzed condensations of aldehydes and ketones such as benzaldehyde with N,N-bis(trimethylsilyl)sulfenamide 529 furnish sulfenimides such as 530 in 82-96% yield [103] (Scheme 5.34). 

In the presence of catalytic amounts of Bp3.0Et2 aromatic aldehydes such as benzaldehyde are converted by bis(trimethylsilyl)selenide 604 into hexamethyldi-siloxane 7 and the corresponding trimers, for example 611 in up to 90% yield. On heating with 1,3-dienes such as 2,3-dimethylbutadiene trimers such as 611 react to give the Diels-Alder product 612 [155] (Scheme 5.49). 

Silylation of hydroxylamine or N-alkyl or N-ethoxycarbonyUiydroxylamines is usually accomphshed, in 52-84% yield, by silylation with TCS 14/NEt3 [63, 161, 162]. Whereas the reaction of N,0-bis(trimethylsilyl)methylhydroxylamine 952 with aldehydes such as benzaldehyde, or with ketones, with to adducts such as 953, has already been mentioned at the beginning of Section 7.3 thermal and other reactions of N,0-bis(trimethylsilyl)hydroxylamine 1141 or N-substituted N,0-bis(trimethylsi-lyl)hydroxylamines 1121, 1128, 1131 are discussed in this section. 

The silylated bis-imine of benzil 1508 reacts with benzaldehyde in benzene, at 90 °C, in the presence of catalytic amounts of AICI3, to afford 2,4,6-triphenylimida-zole 521 in 83% yield [49] (Scheme 9.30). 

The N-bis-silylated o-phenylenediamine 1511 reacts with DMF at 120°C to give benzimidazole, in 97% yield, and dimethylamine and hexamethyldisiloxane 7, whereas reaction of benzaldehyde with 1511 gives only 29% 2-phenylbenzimida-zole 1513, because the intermediate benzimidazoline 1512 is only rather slowly dehydrogenated to 1513 [52]. Heating of N,N -bis(trimethylsilyl)ethylenediamine 1514 with DMF affords imidazoline 1515 and dimethylamine and HMDSO 7 ]52] (Scheme 9.32). The lactam 1516 cycHzes analogously with SiCU 57/triethylamine in 63% yield to give 1517 ]53]. 

The formation of ethers such as 1806 by EtsSiH 84b can also be catalyzed by trityl perchlorate to convert, e.g., benzaldehyde in 84% yield into dibenzyl ether 1817 [48]. The combination of methyl phenethyl ketone 1813 with O-silylated 3-phenyl-n-pro-panol 1818, in the presence of trityl perchlorate, leads to the mixed ether 1819 in 68% yield [48] (Scheme 12.15). Instead of trityl perchlorate, the combination of trityl chloride with MesSiH 84a or EtsSiH 84b and sodium tetrakis[3,5-bis-(trifluoro-methyl)phenyl]borane as catalyst reduces carbonyl groups to ethers or olefins [49]. Employing TMSOTf 20 as catalyst gives very high yields of ethers. Thus benzaldehyde reacts with O-silylated allyl alcohol or O-silylated cyclohexanol to give the... 

Under microwave irradiation and applying MCM-41-immobilized nano-iron oxide higher activity is observed [148]. In this case also, primary aliphatic alcohols could be oxidized. The TON for the selective oxidation of 1-octanol to 1-octanal reached to 46 with 99% selectivity. Hou and coworkers reported in 2006 an iron coordination polymer [Fe(fcz)2Cl2]-2CH30H with fez = l-(2,4-difluorophenyl)-l,l-bis[(l//-l,2,4-triazol-l-yl)methyl]ethanol which catalyzed the oxidation of benzyl alcohol to benzaldehyde with hydrogen peroxide as oxidant in 87% yield and up to 100% selectivity [149]. An alternative approach is based on the use of heteropoly acids, whereby the incorporation of vanadium and iron into a molybdo-phosphoric acid catalyst led to high yields for the oxidation of various alcohols (up to 94%) with molecular oxygen [150]. 

With benzaldehyde, no product was obtained with LLB, and LPB gave no ee, but ALB catalysis gave the product in 85% ee and 62% yield. When excess aldehyde was used, bis-hydrophosphinylation was possible (Scheme 5-40). 

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