Free primary

Similarly, the number of agglomerates (or free primary partieles) leaving the MSMPR erystallizer is proportional to /uo/rAt. 

In subsequent studies,22 Sheehan et al. demonstrated that the action of diisopropylcarbodiimide on penicilloate 24, prepared by protection of the free primary amino group in 23 with trityl chloride (see Scheme 6b), results in the formation of the desired -lactam 25 in a very respectable yield of 67 %. In this most successful transformation, the competing azlactonization reaction is prevented by the use of a trityl group (Ph3C) to protect the C-6 amino function. Hydrogenolysis of the benzyl ester function in 25, followed by removal of the trityl protecting group with dilute aqueous HC1, furnishes 6-aminopenicillanic acid (26), a versatile intermediate for the synthesis of natural and unnatural penicillins. 

From intermediate 28, the construction of aldehyde 8 only requires a few straightforward steps. Thus, alkylation of the newly introduced C-3 secondary hydroxyl with methyl iodide, followed by hydrogenolysis of the C-5 benzyl ether, furnishes primary alcohol ( )-29. With a free primary hydroxyl group, compound ( )-29 provides a convenient opportunity for optical resolution at this stage. Indeed, separation of the equimolar mixture of diastereo-meric urethanes (carbamates) resulting from the action of (S)-(-)-a-methylbenzylisocyanate on ( )-29, followed by lithium aluminum hydride reduction of the separated urethanes, provides both enantiomers of 29 in optically active form. Oxidation of the levorotatory alcohol (-)-29 with PCC furnishes enantiomerically pure aldehyde 8 (88 % yield). 

With alkyl-, allyl-, benzyl-, or aryl-Grignard or lithium reagents 72 0,N-acetals 473 give the N,N-bis-silylated primary amines 474 in high yields these are converted by methanol into the free primary amines 44 and MeOSiMc3 13a [60] (Scheme 5.22). 

In 2005 [61], Overman and coworkers described the application of their oxazoline system 41 to synthetically attractive trifluoroacetimidates 44 (Fig. 23) forming trifluoroacetamides 45, which, in contrast to benzamides 40, can be readily transferred into free primary allylic amines. 

Fig. 5.5 The oligopeptide synthesis at cationic micelles using the condensation agent CDI leads to the intermediate (I), which is in equilibrium with an IV-carboxyanhydride (II). A free primary or secondary amino acid reacts with (II) and forms an amide linkage as well as a carbamide terminus. ...

Abstract. Sodium 5-nitrotetrazolate dihydrate (NaNT) is a useful precursor compound for the synthesis of lead-free primary explosives however, currently employed syntheses for the compound are tedious, dangerous, and plagued by impurities. Through comprehensive analysis, we elucidate the identity of the most detrimental impurities and further report an improved procedure for preparation of NaNT, which greatly improves the purity, while avoiding the handling of acid cop-... 

It is interesting to observe here that the above reaction is absolutely quantitative under experimental parameters. Therefore, it forms the basis for the estimation of pharmaceutical substances essentially containing a free primary amino function as already illustrated earlier. 

Note In order to ensure that the extinctions recorded exclusively refer to folic acid (I), and also that they do not necessarily include a contribution from a free-primary-amino-aromatic-moiety obtained from a decomposition product, a blank estimation is always performed with the unreduced solution and an appropriate correction is applied. The colour thus corresponds to a definite quantity of C16H19OfiN7. Thus, we have ... 

It is also possible to generate microcapsules through interfacial polymerization using only one monomer to form the shell. In this class of encapsulations, polymerization must be performed with a surface-active catalyst, a temperature increase, or some other surface chemistry. Herbert Scher of Zeneca Ag Products (formerly Stauffer Chemical Company) developed an excellent example of the latter class of shell formation (Scher 1981 Scher et al. 1998). He used monomers featuring isocyanate groups, like poly(methylene)-poly(phenylisocyanate) (PMPPI), where the isocyanate reacts with water to reveal a free primary amine. Dissolved in the oil-dispersed phase of an oil-in-water emulsion, this monomer contacts water only at the phase boundary. The primary amine can then react with isocyanates to form a polyurea shell. Scher used this technique to encapsulate pesticides, which in their free state would be too volatile or toxic, and to control the rate of pesticide release. 

Fluorescamine will react with free primary amino groups to yield spots that are easily distinguishable under UV light. 231 Secondary amino groups will not react. 

Y.P. Stercho, Ph. Thesis, Drexel University, 1985 Order-Nr. DA 8527707 . .Routes to Optically Active Protected and Free Primary Amines". 

The same regiochemistry is observed when nitroimidazole (48-2, 48-3) acts as a nucleophile in unionized form. Thus, the reaction of a compound with benzoyl-aziridine (49-1) in the presence of boron trifluoride probably involves an initial salt formation with an amide attack by the imidazole results in a ring opening and the formation of the alkylated product (49-2) the free primary amine (49-3) is obtained on basic hydrolysis. Acylation of the primary amine with methyl thiochloroformate gives the corresponding thiourethane, carnidazole (49-4) [52]. 

One of the first compounds to be introduced to the clinic, aztreonam (40-9), has been produced by total synthesis. Constmction of the chiral azetidone starts with amide formation of L-threonine (40-1) via its acid chloride treatment with ammonia leads to the corresponding amide (40-2). The primary amino group in that product is then protected as its carbobenzyloxy derivative (40-3). Reaction of that product with methanesulfonyl chloride affords the mesylate (40-4). Treatment of that intermediate with the pyridine sulfur trioxide complex leads to the formation of the A -sulfonated amide (40-5). Potassium bicarbonate is sufficiently basic to ionize the very acidic proton on the amide the resulting anion then displaces the adjacent mesylate to form the desired azetidone the product is isolated as its tetrabutyl ammonium salt (40-6). Catalytic hydrogenation over palladium removes the carbobenzyloxy protecting group to afford the free primary amine (40-7). The... 

Thus, reaction of tetrahydrofuroic acid (40-1) with triphenylphosphoryl azide leads to isocyanate (40-2). Treatment of this intermediate with benzyl alcohol then affords the corresponding carbamate (40-3). Catalytic hydrogenation removes the benzyloxy group, leading to the free primary amine. That product is then resolved by way of its camphorsulfonyl salt to afford (40-5). Reaction of this intermediate with desamino chloroadenosine (40-6) affords tecadenoson (40-7) [42]. 

In a subsequent study, Miginiac and coworkers examined additions of allenylzinc reagents to an ZV-TMS imine derived from the mono diethyl acetal of acetylene dicarboxaldehyde10. These additions afforded the homopropargylic adducts as the free primary amines (equation 13). 

Lead is present in most of the primary explosives and thus use of such primary explosives results in corresponding adverse environmental impact. Therefore, development of lead-free primary explosives is an important area of research. Several new explosives such as l,3,5-triazido-2,4,6-trinitrobenzene (TATNB) and... 

Free primary amino acids are characterized by the following absorptions (most of the work was done with a-amino acids, but the relative positions of the amino and carboxyl groups seem to have little effect) ... 

The above sugar residues have furauoid rings of high conformational stability, and their natural occurrence may be attributed to this factor. The various polymers also possess free primary hydroxyl groups, which may confer a certain amount of water solubility upon them. These primary hydroxyl groups Would not be available in an aldopentopyranoid structure. 

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