The powerful electron-withdrawing nature of the nitro group means that deprotonation is possible even with quite weak bases. The pKa of MeNO₂ is 10, about the same as phenol.

Protons adjacent to a nitro group are in fact about as acidic as the same proton adjacent to two carbonyl groups; you can think of a nitro group as having double the electron-withdrawing power of a carbonyl group. Nitro-stabilized anions (‘nitronate anions’) react with carbon electrophiles and a wide variety of nitro-containing products can be produced. The anions are not, of course, enolates, but replacing the nitrogen with a carbon should help you to recognize the close similarity of these alkylations with the enolate alkylations described later.

Surprisingly few simple nitroalkanes are commercially available but more complex exam ples can be prepared readily by alkylation of the anions derived from nitromethane, nitro ethane, and 2-nitropropane. For example, deprotonation of nitropropane with butyllithium followed by the addition of butyl iodide gives 3-nitroheptane in good yield. This reaction really does have to be done in two steps: BuLi is not compatible with alkyl halides!

Nitroalkanes can be alkylated in a single step with hydroxide as a base: phase transfer conditions (see p. 585) keep the HO− and the electrophile apart, preventing alcohol formation. The reaction below on the left works despite the quaternary carbon atom in the product. The reaction on the right gives a cyclic nitroalkane: now there really is no alternative: the base and electrophile must cohabit in the reaction mixture, so a weaker base such as potassium carbon ate must be used—hydroxide or amines are no good here because they would undergo substitution reactions with the halide.

اخر الاخبار

اخبار العتبة العباسية المقدسة

قسم الشؤون الدينية يُطلق دورة فقهية دينية لملاكات مستشفى الكفيل

شعبة فاطمة بنت أسد للدراسات القرآنية تعلن نتائج مسابقة (ميثاق الرسول)

شعبة الخطابة الحسينية النسوية تنظّم مسابقة فرقية لطالبات برنامج ثمار العطاء

قسم العلاقات ينظم ورشة عن فن الإقناع والتواصل الفعّال للطلبة المنسقين

المزيد

الآخبار الصحية

تغيير بسيط في نمط التفكير قد يحدث فرقا كبيرا لصحة الدماغ ؟

لماذا ينعشنا المشروب الساخن في الطقس الحار؟

علماء يكتشفون فئة دم فريدة من نوعها في العالم !

لماذا ينصح الأطباء بزيت الزيتون يوميا؟

المزيد

الآخبار التكنلوجية

حساس الإطارات.. ما هو وعلامات تلفه وكيفية صيانته؟

ما معنى أودي Quattro؟ سر الأداء والتميز الهندسي ؟!

فصل الشاحن أم الهاتف أولا؟.. عادات بسيطة تطيل عمر البطارية

تعود للقرن الرابع قبل الميلاد.. اكتشاف بقايا "إيمت" المصرية

المزيد

مواضيع ذات صلة

Alkylation of nitriles

Some important considerations that affect all alkylations

Conjugate addition

Electrophilic attack on conjugated dienes

Regiospecific preparation of allylic chlorides

Nucleophilic attack on allylic compounds

Radical abstraction

Radical addition

Electrophilic attack on alkenes

Regioselectivity of intramolecular reactions

Regiocontrol by choice of route

Regioselective reactions of naphthalene