Nomenclature Of Hetero Compound for 3rd year Chemistry&physics

الإثنين نوفمبر 09, 2009 12:47 pm

Heterocyclic Compounds

Compounds classified as heterocyclic probably constitute the largest and most varied family of organic compounds. After all, every carbocyclic compound, regardless of structure and functionality, may in principle be converted into a collection of heterocyclic analogs by replacing one or more of the ring carbon atoms with a different element. Even if we restrict our consideration to oxygen, nitrogen and sulfur (the most common heterocyclic elements), the permutations and combinations of such a replacement are numerous.

Nomenclature

Devising a systematic nomenclature system for heterocyclic compounds presented a formidable challenge, which has not been uniformly concluded. Many heterocycles, especially amines, were identified early on, and received trivial names which are still preferred. Some monocyclic compounds of this kind are shown in the following chart, with the common (trivial) name in bold and a systematic name based on the Hantzsch-Widman system given beneath it in blue. The rules for using this system will be given later. For most students, learning these common names will provide an adequate nomenclature background.

[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة]

[center]An easy to remember, but limited, nomenclature system makes use of an elemental prefix for the heteroatom followed by the appropriate carbocyclic name. A short list of some common prefixes is given in the following table, priority order increasing from right to left. Examples of this nomenclature are: ethylene oxide = oxacyclopropane, furan = oxacyclopenta-2,4-diene, pyridine = azabenzene, and morpholine = 1-oxa-4-azacyclohexane.

Element	oxygen	sulfur	selenium	nitrogen	phosphorous	silicon	boron
Valence	II	II	II	III	III	IV	III
Prefix	Oxa	Thia	Selena	Aza	Phospha	Sila	Bora

The Hantzsch-Widman system provides a more systematic method of naming heterocyclic compounds that is not dependent on prior carbocyclic names. It makes use of the same hetero atom prefix defined above (dropping the final "a"), followed by a suffix designating ring size and saturation. As outlined in the following table, each suffix consists of a ring size root (blue) and an ending intended to designate the degree of unsaturation in the ring. In this respect, it is important to recognize that the saturated suffix applies only to completely saturated ring systems, and the unsaturated suffix applies to rings incorporating the maximum number of non-cumulated double bonds. Systems having a lesser degree of unsaturation require an appropriate prefix, such as "dihydro"or "tetrahydro".

Ring Size	3	4	5	6	7	8	9	10
Suffix Unsaturated Saturated	irene irane	ete etane	ole olane	ine inane	epine epane	ocine ocane	onine onane	ecine ecane

Despite the general systematic structure of the Hantzsch-Widman system, several exceptions and modifications have been incorporated to accomodate conflicts with prior usage. Some examples are:
• The terminal "e" in the suffix is optional though recommended.
• Saturated 3, 4 & 5-membered nitrogen heterocycles should use respectively the traditional "iridine", "etidine" & "olidine" suffix.
• Unsaturated nitrogen 3-membered heterocycles may use the traditional "irine" suffix.
• Consistent use of "etine" and "oline" as a suffix for 4 & 5-membered unsaturated heterocycles is prevented by their former use for similar sized nitrogen heterocycles.
• Established use of oxine, azine and silane for other compounds or functions prohibits their use for pyran, pyridine and silacyclohexane respectively.

Examples of these nomenclature rules are written in blue, both in the previous diagram and that shown below. Note that when a maximally unsaturated ring includes a saturated atom, its location may be designated by a "#H " prefix to avoid ambiguity, as in pyran and pyrrole above and several examples below. When numbering a ring with more than one heteroatom, the highest priority atom is #1 and continues in the direction that gives the next priority atom the lowest number.

[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة]
All the previous examples have been monocyclic compounds. Polycyclic compounds incorporating one or more heterocyclic rings are well known. A few of these are shown in the following diagram. As before, common names are in black and systematic names in blue. The two quinolines illustrate another nuance of hetrocyclic nomenclature. Thus, the location of a fused ring may be indicated by a lowercase letter which designates the edge of the heterocyclic ring involved in the fusion, as shown by the pyridine ring in the green shaded box.
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة]

الإثنين نوفمبر 09, 2009 6:30 pm

انا مش فى علوم بس درست الهيتيرو
بجد الله يكون فى عون اللى بيدرسه
وربنا مع اللى بيدرسه يوفقه فيه

الإثنين نوفمبر 09, 2009 8:41 pm

شكرا على مرورك انا بدرس هيتيرو هو فرع عايز فهم اوى وحفظ

الإثنين نوفمبر 09, 2009 9:22 pm

ربنا معاك فيها
هى فعلا فرع محتاج فهم جامد جدا وحفظ
هى الصراحه فرع رخم من الاخر

الثلاثاء نوفمبر 10, 2009 8:37 pm

فعلا عندك حق هى فرع رخم جدا وتقيل كمان والمشكله انو معاه فرع تانى ارخم alicyclic يعنى ماده رخمه رخمه

الجمعة نوفمبر 13, 2009 7:37 am

ربنا يوفقك فيها
ويوفق كل اللى بيدرسوها ان شاء الله

Nomenclature Of Hetero Compound for 3rd year Chemistry&physics

Nomenclature Of Hetero Compound for 3rd year Chemistry&physics

رد: Nomenclature Of Hetero Compound for 3rd year Chemistry&physics

رد: Nomenclature Of Hetero Compound for 3rd year Chemistry&physics

رد: Nomenclature Of Hetero Compound for 3rd year Chemistry&physics

رد: Nomenclature Of Hetero Compound for 3rd year Chemistry&physics

رد: Nomenclature Of Hetero Compound for 3rd year Chemistry&physics