Ethanolamine aldehydes

Zolfigol et al. [66] reported the synthesis of 1,4-DHP derivatives 46 and 47 under mild and solvent-free conditions using a mixture of ethanolamine, aldehydes, and methyl acetoacetate in the presence of acetic acid and iodine as a catalyst for the synthesis of 1,4-DHPs (Schemes 10.30 and 10.31). 

The 5-nitrosallcylaldehyde reagent is prepared as follows. Add 0-5 g. of 5-nitrosalicylaldehyde (m.p. 124-125°) to 15 ml. of pure triethanolamine and 25 ml. of water shake until dissolved. Then introduce 0-5 g. of crystallised nickel chloride dissolved in a few ml. of water, and dilute to 100 ml. with water. If the triethanolamine contains some ethanolamine (thus causing a precipitate), it may be necessary to add a further 0 - 5 g. of the aldehyde and to filter off the resulting precipitate. The reagent is stable for long periods. 

The oxazoloquinolinequinone derivative 610 was prepared from the allylphenol 605 which was transformed to the alcohol 606 and then to the aldehyde 607. Subsequent debenzylation gave 608 that was oxidized with Ce(NH4)2(N02)6 to the quinone 609 that upon cyclization with ethanolamine gave the oxazoloquinolinequinone 610 which showed... 

High boiling polar compounds, diols, phenols, methyl esters of. dicarboxylic acids, amines, diamines, ethanolamines, amides, aldehydes and ketones. 

Allylic boranes such as 9-allyl-9-BBN react with aldehydes and ketones to give allylic carbinols. The reaction begins by Lewis acid-base coordination at the carbonyl oxygen, which both increases the electrophilicity of the carbonyl group and weakens the C-B bond to the allyl group. The dipolar adduct then reacts through a cyclic TS. Bond formation takes place at the 7-carbon of the allyl group and the double bond shifts.36 After the reaction is complete, the carbinol product is liberated from the borinate ester by displacement with ethanolamine. Yields for a series of aldehydes and ketones were usually above 90% for 9-allyl-9-BBN. 

Azaacetals Oxazolidines are formed from ethanolamines and aldehydes or ketones. The C-O bond in oxazolidines can be cleaved selectively by catalytic hydrogenolysis (Scheme 4.15). 

Figure 1.124 Aldehyde groups may be blocked with Tris or ethanolamine using a reductive amination process.

To block unreacted aldehyde sites, add 20 pi of 3 M ethanolamine (pH adjusted to desired value with HC1) per ml of the conjugation solution volume. React for 15 minutes at room temperature. 

Block unreacted aldehydes by the addition of 50 pi of 1M ethanolamine, pH 7.5, per ml of reaction solution. Block for 30minutes at room temperature with mixing. 

Add to the particle suspension a quenching molecule (such as glycine, ethanolamine, or Tris) to give a final concentration of 0.2 M. The blocking agent will couple to any remaining aldehyde-reactive sites. 

Block unreacted aldehyde sites by addition of 50 pi of 1M ethanolamine, pH 9.6, per ml of conjugation solution. Approximately a 1M ethanolamine solution may be prepared by addition of 300 pi ethanolamine to 5 ml of deionized water. Adjust the pH of the ethanolamine solution by addition of concentrated HC1, while keeping the solution cool on ice. 

Ethanolamine is used to displace the adduct from the borinate ester. The facility with which the transfer of acetylenic groups occurs is associated with the relative stability of the. v/ -hybridizcd carbon. This reaction is an alternative to the more common addition of magnesium or lithium salts of acetylides to aldehydes. 

The ozonides of choline and ethanolamine phosphatides subjected to reduction with PhsP yield the corresponding core aldehydes. After hydrolysis with phospholipase C to eliminate the polar group and silylation with trimethylsilyl chloride, the core aldehydes can be determined by GLC-FID using temperature programming to high temperatures . ... 

The ozonides of choline and ethanolamine phosphatides and triglycerides can be subjected to reduction with triphenylphosphine to yield the corresponding core aldehydes, and further derivatized to the 2,4-dinitrophenylhydrazones (DNP). The core aldehydes and their DNP derivatives can be separated by HPLC and characterized by various techniques, including EI-MS and TS-MS of positive and negative ions . See also Section VHI.E. 

The oxazolidine system proved a good protecting group with which to mask the ethanolamine moiety in the a-formylation and a-benzoylation of 558, and it could also be used as an aldehyde donor in the rearrangement, based on the ring-chain tautomeric character of 559, under acidic conditions to yield 3-(2-hydroxyethyl)-substituted 1,3-oxazin-4-ones 560 (Scheme 106) <1996JOC3358>. 

Block unreacted aldehyde sites by addition of 50 pi of 1 M ethanolamine, pH... 

---