Amines are good nucleophiles, but reactions between ammonia and alkyl halides rarely lead cleanly to single products. The problem is that the product of the substitution is at least as nucleophilic as the starting material, so it competes for reaction with the alkyl halide.

Even this is not all! The alkylation steps keep going, forming the secondary and tertiary amines, and stopping only when the non-nucleophilic tetra-alkylammonium ion R4N+ is formed. The problem is that the extra alkyl groups push more and more electron density onto N, making each product more reactive than the previous. The quaternary ammonium salt could probably be made cleanly if a large excess of alkyl halide RX is used, but other more controlled methods are needed for the synthesis of primary, secondary, and tertiary amines. One solution for primary amines is to replace ammonia with azide ion N₃⁻.

This linear tri atomic species, nucleophilic at both ends, is a slender rod of electrons able to insert itself into almost any electrophilic site. It is available as the water-soluble sodium salt NaN3.

Azide reacts only once with alkyl halides because the product, an alkyl azide, is no longer nucleophilic. However, rarely is the azide product required: it is usually reduced to a primary amine by catalytic hydrogenation (H₂ over a Pd catalyst—see Chapter 23), LiAlH₄, or triphenylphosphine.

Azides react with epoxides too. This epoxide is one diastereoisomer (trans) but racemic and the symbol (±) under each structure reminds you of this (Chapter 14). Azide attacks at either end of the three-membered ring (the two ends are the same) to give the hydroxy-azide. The reaction is carried out in a mixture of water and an organic solvent with ammonium chloride as buffer to provide a proton for the intermediate. Triphenylphosphine in water is used for reduction to the primary amine.

اخر الاخبار

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قسم الشؤون الفكرية يطلق باقة من النشاطات الرقمية الخاصة بشهر المحرم

العتبة العباسية المقدسة تختتم السلسلة الأولى لمشروع المحاضرات القرآنية العاشورائية في بابل

العتبة العباسية المقدسة تسلّم راية العزاء إلى تجمّع مواكب محافظة الديوانية

قسم الشؤون الفكرية يواصل إقامة المجالس الحسينية ضمن سلسلة (بيوت النعيم)

المزيد

الآخبار الصحية

لكبح الجوع وخسارة الوزن.. "سر بسيط" في نظام جوكوفيتش ؟

هل يساعد الرجيم في علاج الأمراض العقلية؟

لحماية أسنان طفلك.. هذا الفيتامين يقلل خطر التسوس

أكل الطعام بسرعة.. طريق سريع إلى أمراض خطيرة

المزيد

الآخبار التكنلوجية

ما هي أفضل درجة حرارة لتكييف الهواء في السيارة؟

ذوبان الأنهار الجليدية يوقظ "عمالقة نائمة"!

9 يوليو يشهد أقصر يوم في التاريخ المسجل ؟!!

راتبه عشرات ملايين الدولارات.. زوكربرغ يخطف "عقل أبل"

المزيد

مواضيع ذات صلة

Synthons are idealized reagents

The E-selective Wittig reaction

The Z-selective Wittig reaction

The Peterson reaction is stereospecific

The one-step Julia olefination

The Julia olefination is stereoselective

Sulfoxide elimination—oxidation to enones

Addition of nucleophiles to alkynes

E-selective reduction of alkynes using sodium in liquid ammonia

Amine synthesis using functional group interconversions

Functional group interconversion

Multiple step syntheses: avoid chemoselectivity problems